reference jet fuels for combustion testing

58
American Institute of Aeronautics and Astronautics 1 Reference Jet Fuels for Combustion Testing Tim Edwards 1 Air Force Research Laboratory, Dayton, OH, 45433 This paper provides a summary of the composition and properties of reference jet fuels used in the National Jet Fuel Combustion Program. Additional data is provided for common alternative jet fuels. Two classes of fuels are discussed: (1) “Category A” fuels which represent the range of properties seen in current petroleum-derived jet fuels, and (2) “Category C” test fuels which have certain properties well outside of experience. Combustion test and modeling results for a number of these fuels are becoming available in the literature, with this paper serving as a detailed reference on the properties of these reference fuels. Nomenclature AFPET - Air Force Petroleum Agency AFRL - Air Force Research Laboratory ASTM - American Society for Testing and Materials (ASTM International) ATJ - Alcohol-to-jet (alternative jet fuel) Cp = Heat capacity (of fuel) Cx = Hydrocarbon fuel component with x atoms of carbon per molecule CRATCAF Combustion Rules and Tools for the Characterization of Alternative Fuels (program) CRC - Coordinating Research Council CTL = Coal-To-Liquid (Fischer-Tropsch) DLA - Defense Logistics Agency F-T = Fischer-Tropsch fuel processing FAA - Federal Aviation Administration (United States) FAME - Fatty Acid Methyl Ester (biodiesel) GTL = (natural) Gas-To-Liquid (Fischer-Tropsch) Hcontent = Hydrogen content in the fuel by mass HEFA - Hydroprocessed Esters and Fatty Acids (alternative jet fuel) HOC = Heat of Combustion (MJ/kg) (net) HRJ = Hydrotreated Renewable Jet (fuel) predecessor name for HEFA IPK = Iso-Paraffinic Kerosene (Sasol) MURI = Multidisciplinary University Research Initiative MW = Average Molecular Weight of a complex fuel NJFCP - National Jet Fuel Combustion Program OEM - Original Equipment Manufacturer POSF - fuel designation, not an acronym PQIS - Petroleum Quality Information System (DLA database) P = Pressure (bar or atm) SPK - Synthetic Paraffinic Kerosene (alternative jet fuel) SwRI - Southwest Research Institute, San Antonio, Texas T = Temperature (K) UDRI - University of Dayton Research Institute WPAFB - Wright-Patterson Air Force Base 1 Principal Chemical Engineer, Aerospace Systems Directorate, AFRL/RQ, WPAFB, OH 45433; AIAA Associate Fellow

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Page 1: Reference Jet Fuels for Combustion Testing

American Institute of Aeronautics and Astronautics

1

Reference Jet Fuels for Combustion Testing

Tim Edwards1

Air Force Research Laboratory, Dayton, OH, 45433

This paper provides a summary of the composition and properties of reference jet fuels

used in the National Jet Fuel Combustion Program. Additional data is provided for common

alternative jet fuels. Two classes of fuels are discussed: (1) “Category A” fuels which represent

the range of properties seen in current petroleum-derived jet fuels, and (2) “Category C” test

fuels which have certain properties well outside of experience. Combustion test and modeling

results for a number of these fuels are becoming available in the literature, with this paper

serving as a detailed reference on the properties of these reference fuels.

Nomenclature

AFPET - Air Force Petroleum Agency

AFRL - Air Force Research Laboratory

ASTM - American Society for Testing and Materials (ASTM International)

ATJ - Alcohol-to-jet (alternative jet fuel)

Cp = Heat capacity (of fuel)

Cx = Hydrocarbon fuel component with x atoms of carbon per molecule

CRATCAF Combustion Rules and Tools for the Characterization of Alternative Fuels (program)

CRC - Coordinating Research Council

CTL = Coal-To-Liquid (Fischer-Tropsch)

DLA - Defense Logistics Agency

F-T = Fischer-Tropsch fuel processing

FAA - Federal Aviation Administration (United States)

FAME - Fatty Acid Methyl Ester (biodiesel)

GTL = (natural) Gas-To-Liquid (Fischer-Tropsch)

Hcontent = Hydrogen content in the fuel by mass

HEFA - Hydroprocessed Esters and Fatty Acids (alternative jet fuel)

HOC = Heat of Combustion (MJ/kg) (net)

HRJ = Hydrotreated Renewable Jet (fuel) – predecessor name for HEFA

IPK = Iso-Paraffinic Kerosene (Sasol)

MURI = Multidisciplinary University Research Initiative

MW = Average Molecular Weight of a complex fuel

NJFCP - National Jet Fuel Combustion Program

OEM - Original Equipment Manufacturer

POSF - fuel designation, not an acronym

PQIS - Petroleum Quality Information System (DLA database)

P = Pressure (bar or atm)

SPK - Synthetic Paraffinic Kerosene (alternative jet fuel)

SwRI - Southwest Research Institute, San Antonio, Texas

T = Temperature (K)

UDRI - University of Dayton Research Institute

WPAFB - Wright-Patterson Air Force Base

1 Principal Chemical Engineer, Aerospace Systems Directorate, AFRL/RQ, WPAFB, OH 45433; AIAA Associate

Fellow

Page 2: Reference Jet Fuels for Combustion Testing

American Institute of Aeronautics and Astronautics

2

I. Introduction

The ongoing effort to evaluate the performance of alternative aviation fuels has renewed the interest in the effect

of jet fuel composition changes on gas turbine operability and performance. Aviation’s current focus is on “drop-in

fuels”, which are composed solely of hydrocarbons, but produced from alternative sources/feedstocks such as biomass.

Aviation is not considering oxygenated jet fuel components such as alcohols or fatty acid methyl esters (FAMEs) due

to their negative impacts on performance and handling. A previous paper [1] described an ongoing program to

streamline the combustion evaluation of alternative aviation fuels under the umbrella of the National Jet Fuel

Combustion Program (NJFCP) – this paper is a significant expansion of the fuels section of that paper. Based on

requirements developed in an earlier program (Combustion “Rules and Tools” or CRATCAF [2]), the NJFCP program

has developed/acquired a suite of conventional jet fuels and “test fuels” to characterize the fuel sensitivity/response

of combustion devices. These fuels were developed to span the range of jet fuel composition and properties that could

be encountered with conventional and alternative jet fuels. The fuels are being acquired and distributed by the Air

Force Research Laboratory’s Fuels Branch in Dayton Ohio. AFRL has also distributed “typical” and “average” fuels

to the research community in the past, and some of these fuels will be included in this paper. This paper will also

include the properties of common alternative jet fuels distributed by AFRL. The test fuels and alternative fuels do not

meet the all the jet fuel specifications (such as density); the test fuels were designed to explore a particular aspect of

the fuel property/composition space such as boiling range or viscosity, while many of the alternative fuels have been

approved in fuel specifications such as ASTM D7566 for use as 50% blends (or less) with conventional fuels. The

“Rules and Tools” program had defined several categories of fuels to be used to characterize fuel effects on

combustion, some of which are being carried forward by NJFCP:

Category A - conventional fuels derived from petroleum, encompassing the range of properties typically

encountered (viscosity, flash point, aromatic content, etc.)

Category B – alternative jet fuels found to have unacceptable combustion properties (not used in NJFCP)

Category C – test fuels designed to explore the “edges” of the jet fuel composition-property space, such as

fuels being at the viscosity limit of the specification or fuels whose composition is outside of typical

experience (such as cycloparaffin content)

This paper includes data for Category A and Category C fuels as utilized by the NJFCP, as well as data for common

alternative fuels. The data presented includes:

Specification properties important to combustion: flash point, viscosity, aromatic content, hydrogen content,

ASTM D86 distillation, smoke point, measured heat of combustion, measured cetane number

Composition: GCxGC distribution of major hydrocarbon classes across carbon number, average molecular weight

“Fit-for-purpose properties” - density vs T, viscosity vs T, Cp vs T, surface tension vs T, vapor pressure vs T

ASTM Calculation methods for properties such as heat of combustion (ASTM D3338), hydrogen content (ASTM

D3343), and cetane index (ASTM D4737) are typically not validated for alternative fuels or “test fuels” and thus are

not included, with this paper focusing on the actual measurements. Cetane index (calculation) has been found to be

very inaccurate for some alternative fuels. Note that oxygenate-free jet fuels allow hydrogen content to be converted

to H/C ratio directly by making the valid assumption that the non-hydrogen portion of the fuel is entirely carbon.

Also included as part of the data is the AFRL identification number, which identifies specific batches of fuel. This

ID number takes the form of POSF XXXXX, where POSF is the Fuels Branch’s organizational designation back in

1981 when the numbering began (with 001), thus it is NOT an acronym. The number are assigned roughly in order

received, with POSF 10000 assigned in late 2012.

When available, comparison data is presented from common sources, such as the Coordinating Research Council’s

(CRC) Handbook of Aviation Fuel Properties [3], the CRC World Fuel Sampling Program [4] (often termed the World

Survey), and the Defense Logistics Agency’s (DLA) Petroleum Quality Information Service (PQIS) database [5].

There is a current FAA program collating airport property data that should generate a very useful set of data available

in 2017. There are a number of petroleum industry references for calculating most physical properties of petroleum

fractions such as jet fuel, typically using commonly measured properties such as specific gravity/density and mean

boiling point from ASTM D86 [6,7,8]. Thus, while the ASTM D86 distillation does not represent a true boiling curve

for jet fuels, its use since the 1930s allows it to be correlated to a large amount of historical data. NIST has developed

an “advanced distillation” method, and has recently published data on Category A fuels [30]. NIST has also very

Page 3: Reference Jet Fuels for Combustion Testing

American Institute of Aeronautics and Astronautics

3

recently published densities of the Category A fuels as a function of pressure up to 45 MPa [31]. The densities

presented in this paper are the conventional jet fuel densities by ASTM D4052 at 1 atm. Other properties are also

measured at atmospheric pressure – a potential shortcoming for applications at high pressure such as aviation diesel

engines with high-pressure common rail fuel injectors.

The NJFCP program is also a successor to earlier DoD and NASA programs in the late 1970s (e.g., [9]), which

looked at the effect of fuel composition and property changes on 1970s-vintage combustors. These earlier programs

also focused on “broadened” jet fuel specifications that could be used to increase supply, such as increasing the jet

fuel aromatic limit above 25 vol%. In contrast, NJFCP is looking at the effects on current and future combustor

operability of various jet fuel composition changes that might be driven by modern alternative (bio) fuels.

II. Conventional/Reference Fuels – “Category A” A. Overview

The Category A jet fuels were defined by selecting important combustion-related properties and attempting to find

production fuels that would represent the range of properties of jet fuels in use today. The CRATCAF program

included a detailed literature review of prior work, from which the OEMs selected three combustion-related properties

that represented the variations seen in practice - flash point, viscosity, and aromatics content - that would be expected

to have the greatest impact on combustor behavior. Three fuels were sought: a fuel with low flash/viscosity/aromatics

(“A-1”), “average/nominal” properties (“A-2”), and high flash/viscosity/aromatics (“A-3”). Table 1 shows the OEM-

selected desired properties. Cliff Moses, retired from Southwest Research Institute, referenced the Petroleum Quality

Information System (PQIS) database from DLA to identify originating sources for these three fuels. It was desired

that 6,000 gallons (23,000 L) be obtained for the A-1 and A-3 fuels, and 22,000 gallons (83,000 L) for the “nominal”

A-2 fuel. After some time (and effort), suitable fuels were identified and obtained directly from refineries (many

refineries have no ability to load trucks). The A-2 fuel (POSF 10325) was a Jet A procured from the Shell Mobile*

refinery in June 2013. The A-1 fuel was a JP-8 fuel procured from NuStar Refining* in April 2013. The A-3 fuel

was a JP-5 fuel from Valero* procured in May 2013. As shown in Table 1, the average/nominal fuel goals were met

with A-2. The A-1 fuel goals were nearly met. The A-3 (JP-5) had a flash point lower than desired. (It was

demonstrated at AFRL that, if necessary, the flash point of this fuel could be raised to 70 °C by distilling off the lower

boiling components.) Also, the aromatic goal was not met – but the hydrogen content of this fuel is 13.4 mass% (due

to high cycloparaffin content), which is the lower limit of JP-8 specifications and is at the low end of the jet fuel

“experience base”. Previous programs (such as described in [9]) have shown that fuel soot production is controlled

by overall fuel hydrogen content or H/C ratio for hydrocarbon fuels, rather than by aromatic level. This has been

verified in engine testing where aromatic-free but decalin-rich fuels burn very similarly to fuels with 25% aromatics

and the same hydrogen content.

*Any identifications of commercial products within this paper is for information only and does not indicate

recommendation or endorsement by FAA, AFRL, or DLA.

Table 1. Pertinent Properties of Procured Category A Conventional Fuels

Fuel Flash Point, °C Viscosity, mm2s-1 (cSt)

( at -20 °C)

Aromatics, % (vol)

Desired Actual Desired Actual Desired Actual

A-1, POSF

10264

≤40 42 ≤3.4 3.5 ≤14 11.2

A-2, POSF

10325

50±3 48 4.5±0.5 4.5 17±1 17.0

A-3, POSF

10289

≥66 60 ≥6.5 6.5 ≥21 18.0

Page 4: Reference Jet Fuels for Combustion Testing

American Institute of Aeronautics and Astronautics

4

B. Specification Properties

Specification properties were obtained from the Air Force Petroleum Agency laboratory at WPAFB, the University

of Dayton’s laboratories at WPAFB, and Southwest Research Institute in San Antonio TX. Not surprisingly, the fuel

properties cannot be varied independently; rather they are interdependent. For example, distilling off portions of a

fuel to change the flash point or the freeze point also affects the distillation curve (obviously) and also affects the

viscosity significantly. The heat of combustion is directly related to the fuel hydrogen content – and properties of

most (petroleum-derived) fuels in general can be correlated to the fuel density and average molecular weight/boiling

range [6]. A complete set of specification properties was obtained for the Category A fuels. A summary of key

properties of the fuels is given in Figure 1, which shows that the three fuels do indeed encompass a wide range of

properties within the jet fuel “experience base”. Tabular data is shown in Appendix A. All three fuels are relatively

wide-boiling middle distillate fuels. This characteristic is important to note since narrow-boiling fuels will be a target

of research through “Category C” “test fuels” described below. The boiling ranges of the three fuels are illustrated in

Figure 2. The D86 limits for jet fuel (ASTM D1655) and kerosene (ASTM D6399) are T10 < 205 C and final boiling

point <300 C. Note that jet fuel, kerosene, and diesel fuel are all “middle distillates” per ASTM D4175, but kerosene

and jet fuel fall into the class of “light” middle distillates. Diesel fuel (per ASTM D975) also uses D86, but has 282 C

<T90 <338 C, thus has a significantly higher boiling point at the end of the distillation curve.

The combustion-related specification properties are shown in Table 2. For reference, the effect on the boiling

range of distilling off the “light ends” of the A-3 fuel to raise its flash point to 70 C is shown in Figure 3. Raising the

flash point from 60 to 70 C also increases the viscosity at -20 C from 6.5 to 6.8 cSt and raises the freeze point from -

50 C to -49 C. This increased viscosity/freeze point is probably the explanation why the A-3 fuel in Figure 2 has had

some of the higher-boiling material removed and has a lower final boiling point than the “average” fuel – the higher-

boiling materials has been removed to meet the JP-5 freeze point and viscosity requirements. Comparison of various

specification distillation methods (ASTM D86, D7345, and D2887) for the three Category A fuels is presented in

Appendix C. D86 data can be converted to true boiling point data using equation 3.14 in Reference 6. As shown in

Appendix C, ASTM D86 does not represent the true boiling point, but has been in use since the 1930s to conveniently

characterize petroleum fractions like jet fuel. Reference 6 defines “narrow boiling [petroleum] fraction” as one whose

ASTM 10-90% distillation slope is < 0.8 C/%. As discussed later, jet fuels are typically right at this limit, so can be

defined as “narrow boiling” with caution.

As mentioned previously, the Category A fuels do encompass the wide variety of jet fuels produced (as desired).

For example, the range of densities seen in the PQIS data base is shown in Figure 4, with the A-1 and A-3 fuels well

out on the ends of the distribution as desired. Density was not a criteria for the Category A fuels, but the viscosity

and aromatic requirements also effectively drove the density of the fuels to the edges of the distribution.

Figure 1. Property Range of the Category A Conventional Fuels with Respect to Allowed Limits (Red

Established, Yellow Proposed)

Page 5: Reference Jet Fuels for Combustion Testing

American Institute of Aeronautics and Astronautics

5

Table 2 – Specification Test Results for Category A Fuels (from AF Petroleum Agency unless otherwise noted)

Category A Fuels

Property Test

Method

Spec limits A-1, 10264 A-2, 10325 A-3, 10289 PQIS 2012

wt mean

Density D4052 0.775-0.84 0.780 0.803 0.827 0.8022

Flash point, C D93 >38 42 48 60 47.6

Viscosity, -20 C

(cSt)

D445 <8 3.5 4.5 6.5 4.399

Aromatics, vol% D1319 <25 11.2 17.0 18.0 17.1

Heat of

Combustion, MJ/kg

D4809 >42.8 43.2 43.1 43.0 43.2

Heat of

Combustion, MJ/kg

D4809

(SwRI[32])

43.24 43.06 42.88

H content, mass%

(meas) SwRI

D3701 >13.4 14.26 13.84 13.68 n/a

H content, mass %

(meas)

D7171 >13.4 14.4 13.7, 13.9 13.4 n/a

H content, mass % GCxGC

(UDRI)

>13.4 14.4, 14.5 14.0 13.7 n/a

H/C ratio (based on

D3701)

calculation n/a 1.99 1.91 1.89 n/a

Molecular formula GCxGC n/a C10.8H21.8 C11.4H22.1 C11.9H22.6 n/a

Derived cetane #,

SwRI

D6890 n/a 48.8 48.3 39.2 n/a

Distillation, C D86

IBP 145 159 174 160*

10% <205 164 176 192 176*

20% 171 184 199 183*

50% 189 205 218 201*

90% 234 244 244 238*

FBP <300 256 269 258 254*

Engine cetane,

SwRI

D613 n/a 48.0 47.9 40.4 n/a

Smoke pt, mm D1322 >18 28.5 23 20 22.8

Freeze pt, C D5972 >-47 (JP-8) -51 -51 -50 -51.3

*D86 data from World Survey, since PQIS is a combination of D86 and D2887

Page 6: Reference Jet Fuels for Combustion Testing

American Institute of Aeronautics and Astronautics

6

140

160

180

200

220

240

260

280

0 20 40 60 80 100

A-1 10264 AFA-2 10325 AFA-3 10289 AFA-1 10264 SwRIA-2 10325 SwRIA-3 10289 SwRIWorld Survey avg

Te

mpe

ratu

re ,

°C

D86 % Distilled

Figure 2. ASTM D86 distillation for Category A fuels [SwRI]

160

180

200

220

240

260

0 20 40 60 80 100

POSF 10289 - JP-5, 60 C flashPOSF 10376 - JP-5, 70 C flash

Te

mp

era

ture

, C

D86 % Distilled

Figure 3. Change in D86 results obtained by distilling off low boiling point material to raise flash point of

A-3 fuel from 60 to 70 C.

Page 7: Reference Jet Fuels for Combustion Testing

American Institute of Aeronautics and Astronautics

7

0

200

400

600

800

1000

0.775

0.78

0.785

0.79

0.795

0.8

0.805

0.81

0.815

0.82

0.825

0.83

0.835

0.84

Nu

mb

er

of

sa

mp

les

Density

POSF 10289 - 0.827

POSF 10325 - 0.803

POSF 10264 - 0.780

Figure 4. Density histogram from 2013 PQIS, with Category A fuels labeled.

C. Composition

The fuel specification properties don’t control the fuel composition directly, aside from the 25 vol% limit on total

aromatics by ASTM D1319. The indirect effect of the specification limits lead to the distribution of hydrocarbons

shown in Figure 5 (A-2/POSF 10325 “average” Jet A) and Figure 6 (hydrocarbon distribution of 55 World Survey

fuels averaged together). This data comes from GCxGC measurements by UDRI [10]. The lack of hydrocarbons

below about C8 is due to the flash point limit (>38 C). The lack of hydrocarbons above about C17 is due to the freeze

point limit (<-40 C for Jet A) and the D86 end point limit (<300 C) (and influenced by the -20 C viscosity limit).

There are some inter-relations – one can distill off the “light ends” of a fuel to raise the flash point, but that also tends

to increase the viscosity at low temperatures, as mentioned earlier. In any case, typical jet fuels (Figures 5 and 6) have

the four types/classes of hydrocarbons (olefins are low in jet fuels) distributed across many carbon numbers. The

numerical GCxGC data is included in Appendix A. One area where GCxGC is weak is differentiating the level of

branching in iso-paraffins and in side-chains on aromatics and cycloparaffins – which can affect combustion properties

such as cetane number/ignition delay. NMR is good option for this (e.g., Reference 35 for diesel), but NMR data is

not yet available for the Category A fuels. NMR is being used in the development of surrogate fuels, as discussed in

Section VI below.

Reference 30 includes composition estimates for a number of boiling fractions. The aromatics are the only

hydrocarbon class that are not distributed relatively even across the distillation range – the aromatics tend to be

concentrated in the lower-boiling fractions [30].

This data is used to define the compositional “experience base” for current/conventional fuels – important for

evaluating some of the alternative and Category C fuels, whose compositions can be noticeably different from Figure

5 and 6. These figures do confirm that the A-2 fuel is very typical in terms of composition. The composition of the

A-3 and A-1 fuels are shown in Figure 7 and 8, respectively.

Page 8: Reference Jet Fuels for Combustion Testing

American Institute of Aeronautics and Astronautics

8

0

1

2

3

4

5

6

7 8 9 10 11 12 13 14 15 16 17 18

n-paraffinsiso-paraffinsaromaticscycloparaffins

Co

mp

ositio

n,

ma

ss%

Carbon number

Figure 5. Nominal Category A fuel (A-2) composition

0

1

2

3

4

5

6

7

8

7 8 9 10 11 12 13 14 15 16 17 18

n-paraffinsiso-paraffins

aromaticscycloparaffins

Co

mp

ositio

n,

ma

ss %

Carbon Number

Figure 6. Averaged composition of 55 World Survey fuels (Stoddard solvent removed)

Page 9: Reference Jet Fuels for Combustion Testing

American Institute of Aeronautics and Astronautics

9

0

2

4

6

8

10

7 8 9 10 11 12 13 14 15 16

n-paraffinsiso-paraffinsaromaticscycloparaffins

Com

positio

n,

mass%

Carbon number

Figure 7. “A-3” composition

0

2

4

6

8

10

7 8 9 10 11 12 13 14 15 16 17 18

n-paraffinsiso-paraffinsaromaticscycloparaffins

Co

mp

ositio

n,

ma

ss%

Carbon number

Figure 8. “A-1” composition

Page 10: Reference Jet Fuels for Combustion Testing

American Institute of Aeronautics and Astronautics

10

D. Fit-for-Purpose Properties

The alternative fuel approval process (ASTM D4054) defines a class of properties that are not limited by the

specification, but are limited to an expected range for fuels that are acceptable (“fit-for-purpose”). A set of

combustion-relevant physical properties was obtained for the A-1, A-2, and A-3 fuels: density vs T, viscosity vs T, Cp

vs T, surface tension vs T, vapor pressure vs T. Each fit-for-purpose property is discussed separately below. Published

estimation methods are also presented for non-specification properties.

1. Density vs T

The density-vs-temperature line (Figure 9) for the A-1 and A-3 fuels are very consistent with the World Survey

minimums and maximums. The A-2 fuel density and viscosity is close to the average as reflected in the CRC Aviation

Fuel Properties Handbook [3]. Extensive density data on the Category A fuels as a function of pressure has recently

been published by NIST [31]; the lowest pressure data (0.5 MPa) is consistent with the data in Figure 9. Other high

pressure density data [32] is not entirely consistent with Reference 31. Density is a linear function of temperature in

the range shown, which is significantly below the jet fuel critical temperature (~400 C [33]). This is perhaps not

surprising since the density of various pure hydrocarbons and petroleum distillates as a function of temperature has

been shown to have a similar slope versus temperature [34]. For the temperature range shown, it would seem

reasonably accurate to extrapolate density of an unknown jet fuel based on this slope and the 15 C specification

density.

0.74

0.76

0.78

0.8

0.82

0.84

-50 0 50 100 150

DLA 24 10289DLA 23 10264DLA 22 10325

10289 spec10264 spec10325 spec

De

nsity,

g/c

m3

Temperature, C

CRC Handbook Jet A

CRC World Fuel

Survey (max)

CRC World Fuel

Survey (min)

Spec limits at 15 C

Figure 9. Density vs T data for Category A fuels

Page 11: Reference Jet Fuels for Combustion Testing

American Institute of Aeronautics and Astronautics

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2. Viscosity vs T

The kinematic viscosity-vs-temperature line (Figure 10, note strong temperature dependence) shows that the viscosity

of A-1 and A-3 is similar to the minimum and maximum from the World Survey. A-2 is very similar in viscosity

behavior to the average shown in the CRC Handbook. Given the strong temperature dependence of viscosity,

measurements at -20 C (at least) appear to be warranted for any new fuel, rather than an estimate based on ambient

temperature viscosity or based on correlations with other properties. ASTM D7566 has started using a 12 cSt limit at

-40 C for alternative fuels. The data in Figure 10 has been linearized per ASTM D341 using the correlation: log log

(viscosity + 0.7) = A – B Log T, where A and B are constants.

POSF 10264 (A-1)

POSF 10325 (A-2)

POSF 10289 (A-3)

Vis

co

sity,

cS

t

Temperature, C

20

10

1

5

3

2

-20 40 100

World Survey

minimum

World Survey

maximum

CRC Jet A

Figure 10. Viscosity vs T data for Category A fuels. (1 cSt = 0.000001 m2/s)

Page 12: Reference Jet Fuels for Combustion Testing

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3. Other Combustion-Related Properties (not in specification)

A number of other liquid fuel “fit-for-purpose” properties are relevant to combustion – for example, heat capacity,

surface tension, vapor pressure, and thermal conductivity. Measured values of these properties were obtained from

SwRI for the Category A fuels. Calculated values are also available using petroleum industry correlations dating back

many years [6-8]. These properties are usually calculated as a function of density/specific gravity, average boiling

point, and/or equivalent molecular weight. The mean average boiling point is typical used for property correlations,

although Riazi [6] recommends volume average boiling point for Cp. Using the data for the A-2 fuel from Table 2,

some typical calculations will be shown. Some of these correlations are very old – apologies in advance for the

engineering units! API gravity is often used in some of these correlations, where API gravity = (141.5/specific

gravity)-131.5. Specific gravity (SG) = 0.803 in Table 2 for the A-2 fuel gives API gravity = 44.7.

1) Calculate volume average boiling point: (T10+T50+T90)/3 = 208 C (406 F). Note: Riazi [6] states mean average

boiling point ~ T50 for narrow fractions like jet (T50=205 C = 400 F). Charts in Maxwell [8] pg 14-15 give

conversions from volume average boiling temperature to molal, mean average, and weight-average boiling point.

These results are molal average = 396 F, mean average = 400 F, weight average = 404 F.

2) ASTM slope = (T90-T10)/(90%-10%) = 0.85 C/% = 1.5 F/% (small slope indicates small correction in going from

volume average boiling point to molal average boiling point) (unlike crude)

3) Chart in Maxwell [8] gives a characterization factor of 11.85 (or equation Kw=Tb(in R)0.33/specific gravity).

Characterization factor is related to “paraffinicity” of fuel.

4) Fig 5-5 in Nelson [7] yields MW~ 160 (Maxwell [8] ~160); GCxGC ~ 159 (Table 2). Princeton

measurements~148.

5) Check – Riazi [6] has MW=1.6604X10-4 Tb2.1962 SG-1.0164 (Tb in K) ~ 159

6) Dryer et al have patented a direct physical measurement of equivalent molecular weight (patent 9,410,876, August

9, 2016). Comparison ongoing – should use direct measurement if available.

7) Nelson [7] chart for heat of vaporization (HOV) ~115 BTU/lb (267 kJ/kg); Check – CRC gives HOV ~ 275 kJ/kg

at 208 C (118 BTU/lb) – using 208 C as the equivalent “normal boiling point” (nbp) of the A-2 fuel. Riazi equation

for HOV (pg 327, below) ~ 258 J/g at 208 C. Roughly consistent.

∆Hvap (nbp)=37.32315 (Tb1.12086)(SG0.00977089)

Lefebvre [9] has ∆Hvap (nbp)=(360-0.39T[in K])/SG, yielding a HOV value of 307 kJ/kg – a bit higher than the other

results.

8) Riazi has equations for Tc, Pc – 737 F (392 C), 21.2 bar result. Maxwell pg 72 eq has 725F pseudocritical T, true

Tc ~ 735 F. Tc data for jet fuels is typically 700-750 F [33].

References 6-8 can now be used to generate calculated values of heat capacity and surface tension to compare to

measured data.

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13

4. Heat Capacity (Cp) vs T

Heat capacity (Cp) is not a specification property (in contrast to density and viscosity), but is a fit-for-purpose property

and was measured at SwRI for the three Category A fuels using ASTM E1269. The results are shown in Figure 11.

There is some spread in the data, similar to the spread shown in the CRC Handbook [3], which shows differences

among fuels, probably due to density differences. Cp calculations based on density and average boiling point [6-8]

for the A-2 fuel match the data well. But the density difference between A-1 and A-3 in the calculations is not as

large as in the data.

Riazi [6] recommends the use of the Kesler/Lee equation:

CpL=a(b+cT), with T in K and Cp in kJ/kg

a=1.4651+0.2302Kw where Kw is Watson K factor

b=0.306469-0.16734 SG

c=0.001467-0.000551 SG

This equation leads to Cp at 15 C/60 F of 2.06 kJ/kg (A-1), 1.96 (A-2), and 1.94 (A-3). Maxwell [8] has a chart which

yields Cp=1.99 kJ/kg-K for A-2 (and 2.15 for A-1, 1.92 for A-3) at 15 C. Lefebvre [9] includes an equation

Cp=(0.76+0,00335T)/SG0.5, which yields a Cp for A-2 of 1.92 kJ/kg-K at 15 C, pretty consistent with Kesler/Lee

equation. Thus, Maxwell’s charts show a (calculated) spread in Cp across the Category A fuels similar to the SwRI

data, while the Kesler/Lee equation predicts significantly less difference. The CRC Handbook yields a Cp for typical

jet fuels of 1.92 kJ/kg-K at 15 C. The World Survey has Cp data, but as is discussed in an Appendix in that report [3],

there are some issues with the data. Thus, the magnitude of the heat capacity is fairly consistent among the various

sources, so the use of the Cp data for A-2 for a typical jet fuel seems valid. Note that the data for jet fuels presented

in Reference 39 is non-linear with temperature and is inconsistent with the current data.

1.8

2

2.2

2.4

2.6

2.8

-50 0 50 100 150 200 250

POSF 10264, A-1 (light JP-8)POSF 10325, A-2 (avg Jet A)POSF 10289, A-3 (JP-5)CRC JP-5

CRC Jet A/A-1/JP-8CRC JPTS

Calculated [6]

He

at C

apa

city (

Cp

), k

J/k

g-K

Temperature, C

Figure 11. Heat Capacity vs T data for Category A fuels (1 kJ/kg-K = 0.239 BTU/lb-F)

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14

The heat capacity can also be calculated from enthalpy data since Cp is the slope of enthalpy-vs-temperature at a

given temperature. There is some enthalpy data in the literature that can be used to estimate Cp [37]. “The kerosine”

in Reference 37 is very similar to the A-2 fuel, as shown in Figure 12 where the D86 data is compared. The enthalpy

from Reference 37 is shown in Figure 13 for two pressures. The heat capacity at 100 C can be estimated by the

enthalpy change from 24 C to 200 C, divided by the temperature rise. The result is 2.38 kJ/kg-K – very consistent

with Figure 11. Obviously, as the temperature rises above 200 C, fuel vaporization complicates the picture.

Incidentally, Lenoir and Hipkin in Reference 37 use the measured enthalpy data for the kerosene to estimate the critical

condition for this fuel – their tabulated Tc~739 F (393 C) and Pc~361 psia (24.6 atm) are very consistent with the Tc

values calculated above from equations in Riazi [6]. Reference 37 has enthalpy data at a number of pressures – this

data could represent an average jet fuel, given its resemblance to the A-2 fuel. From Figure 13, the heat of vaporization

can be estimated as the enthalpy difference between the fuel initially vaporizing (at ~ 225 C) and completing

vaporization (at above 250 C), which yields a value of approximately 300 kJ/kg – roughly consistent with the results

presented in section 3 above. Lefebvre [9] shows an enthalpy curve for Jet A that is more detailed than Figure 13, but

yields a heat of vaporization of similar magnitude.

140

160

180

200

220

240

260

280

0 20 40 60 80 100

A-2 (POSF 10325)Kerosine [37]

Te

mp

era

ture

, C

D86 % distilled

Figure 12. “Kerosine” D86 data from Reference 37

Page 15: Reference Jet Fuels for Combustion Testing

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15

0

200

400

600

800

1000

0 50 100 150 200 250 300 350

95 atm (1400 psia)

2 atm (30 psia)

En

tha

lpy k

J/k

g

Temperature, C

Ref 37

Figure 13. Enthalpy data for “kerosine” from Reference 37.

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16

5. Surface tension vs T

Similarly to Cp, surface tension (Figure 14) is also not a specification property. In this case, however, the current data

from SwRI using ASTM D1331A (du Noüy ring) does not match well with the CRC Handbook (lower than data) or

with the calculation (higher than data) – although the trends are the same, again the trends are probably due to density

differences. There is surface tension data in the World Survey (higher than SwRI data) – to get a feel for the magnitude

of the density effect, the World Survey data and the current data for A-2 at 22 C is plotted as a function of density in

Figure 15. In this case, the measured data is below the World Survey and the calculations are above, but the trend

with density is correct. Given the disparity of the literature data and the small span of surface tensions covered by the

three Category A fuels, it would seem prudent not to try and draw any conclusion about surface tension effect from

the use of the various Category A fuels.

For the calculations, Riazi [6] (pg 359) has a surface tension equation as a function of reduced temperature (Tr = T/Tc)

and Kw (Watson K factor).

Again, this equation yields trends that agree with the data, but are as far above the data as the CRC results are below

the data. Lefebvre [9] shows a graph of surface tension versus T that is consistent with the CRC Handbook data.

18

20

22

24

26

28

30

32

-40 -20 0 20 40 60

A-1 10264

10264 calcA-2 10325

10325 calc

A-3 1028910289 calc

CRC JPTSCRC Jet A/Jet A-1/JP-8CRC JP-5

Su

rfa

ce

te

nsio

n,

dyne

/cm

Temperature, C

Figure 14. Surface tension vs T data for Category A fuels.

Page 17: Reference Jet Fuels for Combustion Testing

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17

23

24

25

26

27

28

29

0.77 0.78 0.79 0.8 0.81 0.82 0.83

22 CSwRI measurements A-2Calculations [6]World Survey all fuels

Su

rfa

ce

te

nsio

n,

dyn

e/c

m

Density, g/cm3

Figure 15. Surface tension vs density data (22 C) for various fuels.

Page 18: Reference Jet Fuels for Combustion Testing

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18

6. Vapor Pressure vs T

Vapor pressure is not a specification property. Vapor pressure is not independent of the other properties discussed –

it is likely that one could calculate the vapor pressure from the D86 and/or flash point. For example, the CRC

Handbook shows separate vapor pressure curves for JP-8/JetA/Jet A-1 (flash >38 C) and JP-5 (flash > 60 C). The

vapor pressures of the three Category A fuels was measured at SwRI yielding the results shown in Figure 16. And,

yes, the data comes as vapor pressure in psia versus temperature in C, so those mixed units are plotted directly. The

vapor pressures track with D86 and flash point, as expected.

0

1

2

3

4

5

0 50 100 150

10264 JP-8

10325 Jet A

10289 JP-5, psia

CRC JP-8

CRC JP-5

Va

po

r p

ressure

, p

sia

Temperature, C

Range in HEFA

Research Report

Figure 16. Vapor pressure vs T data for Category A fuels

Page 19: Reference Jet Fuels for Combustion Testing

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19

7. Thermal conductivity vs T

Thermal conductivity data was not obtained for the Category A fuels. Thermal conductivity of liquid jet fuel is not a

specification property, and is presented in the CRC Handbook as a single line for all jet fuels (but a line that has moved

over the years – the line from the 2004 Handbook best matches the data collected in the 1980s and 1990s). It has not

been typically measured for alternative fuels due to its expected small variation with fuel composition. Riazi [6]

presents an equation for thermal conductivity that basically “splits the difference” between the two CRC lines (Figure

17) when the values for the A-2 fuel are plugged into the equation.

Where Tb and T are in K and k (thermal conductivity) is in W/m-K. Lefebvre [9] includes a simpler equation:

k=(0.134-0.000063)/SG, which yields a thermal conductivity of 0.143 for A-2 at 15 C, well above any of the data in

Figure 17.

In the absence of other data, approximating the thermal conductivity of a jet fuel with the data from the CRC 2004 (or

later) handbook is probably the best option.

0.1

0.105

0.11

0.115

0.12

0.125

0.13

-20 0 20 40 60 80 100 120

CRC jet 2004CRC jet 1983Riazi equation for A-2

Th

erm

al co

nductivity,

W/m

-K

Temperature, C

Figure 17. Thermal conductivity as a function of temperature

Page 20: Reference Jet Fuels for Combustion Testing

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20

8. Heat of formation

For some computer calculations, the heat of formation of various fuels is needed to calculate flame properties. As

described in Reference 38, the heat of formation can be (back)calculated from the measured hydrogen content and

measured heat of combustion.

CaHb + (a+ (b/4)) O2 a CO2 + (b/2) H2O

a(ΔHf CO2) + (b/2)(ΔHf H2O (gas)) - (ΔHf fuel) – (a+(b/4))(ΔHf O2) = Heat of combustion, in (typically) kcal/mole fuel, ΔHf

where the only unknown in the second equation is the heat of formation of the fuel (since b/a=H/C and the heat of

formation of water and CO2 are known). In this calculation below, the fuel H/C ratio is used to artificially define the

fuel as (e.g.) CH1.9818. This abstraction is used to initially (mis)define a mole of fuel to end up with the heat of

formation in cal/g (as is typical in some calculations). Since a “mole” of fuel, or the fuel equivalent molecular

weight, is an abstraction – typically heat of formation is reported in cal/g. However, an equivalent molecular weight

by GCxGC or other means can be used to get heat of formation in terms of kcal/mol that is more realistic than

defining the fuel as CH1.9818. Such a calculation is performed in Table 3 below. Within the accuracies of the

measured H content and heat of combustion, it appears the heat of formation of the three Category A fuels is

essentially the same.

Table 3. Heat of formation calculations

1 calorie/gram = 4.184 Joules/gram = 1.8 BTU/lb

Fuel wt% H

(meas)

SwRI

D3701

H/C molar

(calc from H

content)

Mass heat of

comb, MJ/kg

(SwRI, meas

D4809)

Mass heat

of comb,

kcal/g

Heat of

formation

(calc), cal/g

MW,

GCxGC

Heat of

formation,

kcal/mol

A-1 10264 14.260 1.9818 43.24 -10335 -467.7 152 -71.1

A-2 10325 13.840 1.9141 43.06 -10292 -423.2 159 -67.3

A-3 10289 13.680 1.8885 42.88 -10249 -432.9 166 -71.9

Page 21: Reference Jet Fuels for Combustion Testing

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21

III. Test Fuels – “Category C” A. Overview of Category C Fuels [1]

The main objective of the Category C “test fuels” was to identify hydrocarbon blends that had “unusual” (outside

of experience) properties, such as narrowly distributed aromatics at the “front end” of the boiling range or high

viscosities. The CRATCAF Phase IIa report [2] had a list of potential blending components and several blended

“fuels” listed for testing in later phases. For the NJFCP, in consultation with the OEMs, six “test fuels” of interest

were selected based on properties and availability; components were acquired in “neat” form as necessary and

blending was performed at AFRL. It was decided that these test fuels were to be tested in their neat form without

blending with petroleum jet fuels to increase the likelihood of observing differences. Thus some of the Category C

fuels do not meet all the jet fuel specifications (like density), so they are best called “test fuels” rather than jet fuels.

Six Category C test fuels were chosen initially for study in Year 1. One of them (C-6, a high-cycloparaffin test

fuel) has not been obtained in sufficient quantities for testing and could not be included in this paper. The

characteristics of the remaining five fuels are compared in Table 4. A seventh Category C test fuel considered was

the high flash point A-3 fuel, with the “front end” of the fuel distilled off to raise the flash point to 70 °C, as described

in the prior section. This test fuel is available for testing in subsequent years if there is interest in a higher-flash-point

fuel. In the 2015 mid-year meeting of the NJFCP team, results for tests of the Category C test fuels were reviewed

and it was decided to focus on the C-1 and C-5 test fuels in the near-term, since the various tests seemed to be the

most sensitive to those fuels, and each represented extremes in chemical and physical properties. Combustion test

results for the various Category C fuels will be reported separately (e.g., [28,29]).

Table 4. Category C Fuel Types

NJFCP Test Fuels

NJFCP Fuel ID C-1 C-2 C-3 C-4 C-5

POSF numbers 11498,

12368,

12384

11813,

12223

12341,

12363

12344, 12489 12345,

12713,

12789, 12816

Composition Gevo ATJ;

C12/C16

highly-

branched

iso-paraffins

84% C14

iso-

paraffins;

16% 1,3,5

trimethyl

benzene

from Swift*

64% A-3;

36% Amyris

farnesane

(C15 iso-

paraffin)

60% Sasol*

IPK (C10-C13

highly

branched iso-

paraffins)/40%

C-1

74% C10 iso-

paraffins,

26% 1,3,5

trimethyl

benzene

Notable

characteristics

Very low

cetane,

unusual

boiling

range

On-spec

fuel,

extremely

chemically-

asymmetric

boiling

range

High

viscosity

fuel, at -20 C

viscosity

limit for jet

fuel

Low cetane,

conventional,

wide-boiling

range

Very flat

boiling range

(fuel boils at

one

temperature)

*Any identifications of commercial products within this paper is for information only and does not indicate

recommendation or endorsement by FAA, AFRL, or DLA.

Page 22: Reference Jet Fuels for Combustion Testing

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22

B. Specification Properties

The specification properties of the various Category C fuels are shown in Table 5.

Table 5 – Category C Fuel Properties

C-1 C-2 C-3 C-4 C-5

Property Test method

Density D4052 0.760 0.781 0.808 0.760 0.769

Flash point, C D93 50 58 66 46 44

Viscosity, -20

C (cSt)

D445 4.9 5.2 8.0, 8.3 3.9 1.9

Aromatics,

vol%

D1319 1 17.6 11.2 2.3 26.2

Heat of

Combustion,

MJ/kg

D4809 AF, SwRI 43.88±0.09

(15 meas.)

43.6, 43.4 43.3, 43.3 43.8, 43.8 42.8, 43.0

H content,

mass%

(meas)

D3701 SwRI 15.28, 15.43 14.42 14.18 15.33 13.96

H content,

mass %

(meas)

D7171 AF 15.2 14.1 14.1 15.5 14.1

H content,

mass %

(meas)

D5291 SwRI 15.34 14.31 14.05 15.33 13.93

H content,

mass%

GCxGC 15.3 14.4 14.2 15.4 13.9

H/C ratio

(based on

D3701)

calculation 2.17 2.00 1.97 2.15 1.94

Molecular

formula

GCxGC C12.6H27.2 C12.4H24.8 C12.8H25.3 C11.4H24.8 C9.7H18.7

Derived

cetane #

D6890 17.1 (range

15.1-18.1)

50.4 47 28 39.6

Smoke pt,

mm

D1322 29.0 30.0 26.0 26.0 25.0

Freeze pt, C D5972 <-61 -45 -54 <-61 -56

Distillation,

C

D86

IBP 173 172 183 161 156

10% 178 190 204 169 161

20% 179 198 212 170 162

50% 182 224 230 179 162

90% 228 233 245 206 164

FBP 263 236 256 239 174

Some of the differences among the Category C test fuels are evident in Figure 18, where the various distillation

curves are plotted (compare to Figure 2 for the petroleum-derived/conventional fuels). C-5 was set up to be a fully-

formulated fuel (including aromatics), but has an extremely flat boiling range (i.e., boiling at essentially one

temperature, like a pure hydrocarbon fluid). This test fuel was created by blending 1,3,5 trimethyl benzene with a C10

iso-paraffinic solvent, both of which boil at roughly 165 °C. This test fuel was designed to evaluate the impact of a

very limited vaporization range of the fuel on combustor operability. However, this fuel also has a low (outside of

experience) viscosity which may impact its performance and make interpretation more difficult. In contrast, the C-2

Page 23: Reference Jet Fuels for Combustion Testing

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23

test fuel is a fully formulated fuel, but has the same low-boiling aromatic compound combined with higher-boiling

C14 iso-paraffins. This fuel is thus the “opposite” of the C-5 fuel in one sense – with one class of materials vaporizing

at an entirely different temperature than the other.

140

160

180

200

220

240

260

280

0 20 40 60 80 100

C-1 11498 AFC-2 12223 AF

C-3 12341 AFC-4 12344 AFC-5 12345 AFC-1 11498 SwRI

C-2 12223 SwRI

C-3 12341 SwrIC-4 12344 SwRIC-5 12345 SwRI

Te

mpe

ratu

re,

°C

D86 % Distilled

"flat"

bimodal

"low cetane bimodal"

"low cetane wide boiling"

"high viscosity"

Figure 18. D86 distillation curves for Category C fuels

The C-1 test fuel is representative of a fuel composed of heavily branched iso-alkanes. This specific fuel is notable

for having two carbons numbers only (12 and 16) and an extremely low derived cetane number (16) relative to other

fuels (typical jet fuels have DCNs of 40-50). Testing of the neat C-1 fuel in this program is to determine the effect of

low cetane on combustor operability. In an attempt to isolate the effect of low cetane number from the unusual carbon

number distribution, the C-4 fuel was created by blending C-1 with a C9 to C12 blend of isoparaffins (Sasol IPK with

a derived cetane number of 31) to create a test fuel with more typical boiling characteristics, but with an intermediate

(but still low) cetane number of 28. The C-3 test fuel was formulated to have a viscosity at the jet fuel specification

limit (8 cSt or mm2s-1 at -20 °C). This test fuel was created by adding farnesane (trimethyl dodecane) to the A-3

conventional high-viscosity JP-5 fuel, with the effect of farnesane addition shown in Figure 19. Note that the C-3 fuel

exceeds the 12 cSt at -40 C limit used in ASTM D7566 – this 12 cSt limit has been proposed to replace the 8 cSt limit

at -20 C to ensure proper APU altitude start after cold soak.

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7

7.2

7.4

7.6

7.8

8

8.2

15 20 25 30 35 40

Vis

co

sity a

t -2

0 C

, cS

t

Vol % farnesane 10370 in JP-5 10289 (A-3)

POSF 12341 = 8 cSt at -20 C

Figure 19. Increase in viscosity by adding farnesane (2,6,10 trimethyl dodecane) to JP-5 (A-3).

C. Composition

The composition of the Category C fuels is simpler in general than that of the Category A fuels. The two simplest

Category C fuels are C-2 (Figure 20) and C-5 (Figure 21). The C-5 fuel was designed to be a fully-formulated fuel

that meets all of the jet fuel specification requirements, but has a very “flat” boiling range (boils at one temperature).

In contrast, the C-2 fuel was designed to be a fully-formulated fuel that had a “bimodal” boiling distribution, with an

aromatic component boiling first, followed by an iso-paraffin. It was determined that isomerization of a C14 alpha-

olefin to the point that it meets the jet fuel freeze point required essentially complete removal of n-C14. As shown in

Figure 20, the C-2 fuel is predominantly C14 iso-paraffins blended with 1,3,5 trimethyl benzene (C9). The thought

behind this fuel was that preferential vaporization (if important) of the trimethyl benzene would create a very difficult

fuel to ignite/burn. In contrast, the C-5 fuel would not have preferential vaporization issues, but might evaporate quite

differently from a conventional fuel. The C-5 fuel’s composition is shown in Figure 21. Figure 18 shows that this

fuel is indeed quite “flat boiling”. Properties of these fuels are shown in Appendix B.

The C-3 fuel is a modification of the A-3 (JP-5) fuel, with its viscosity increased by adding farnesane (2,6,10 trimethyl

dodecane) to hit the specification limit (8 cSt at -20 C), as discussed in reference to Figure 19. The resulting

composition is shown in Figure 22.

The C-1 fuel is was designed to be the lowest cetane jet fuel available, which turned out to the Gevo ATJ fuel,

consisting primarily of C12 and C16 iso-paraffins. There was some concern about the bimodal nature of the D86

curve for this fuel (C-1), so the “C-4” fuel was created by blending in Sasol IPK (another relatively low-cetane fuel,

but one with a very different boiling range. The resulting composition is shown in Figure 23. This fuel has a cetane

number in the mid 20s, but a much broader boiling range.

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0

10

20

30

40

50

60

70

80

7 8 9 10 11 12 13 14 15 16

n-paraffinsiso-paraffins1,3,5 trimethyl benzene

Com

positio

n,

mass%

Carbon number

Figure 20. C-2 fuel composition

0

10

20

30

40

50

7 8 9 10 11 12 13 14 15 16

n-parafffinsiso-paraffins1,3,5 trimethyl benzene

Com

positio

n,

mass%

Carbon number

Figure 21. C-5 fuel composition

Page 26: Reference Jet Fuels for Combustion Testing

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26

0

2

4

6

8

10

7 8 9 10 11 12 13 14 15 16

n-paraffinsiso-paraffinsaromaticscyclo-paraffins

Co

mp

ositio

n,

ma

ss%

Carbon number

36

Figure 22. C-3 fuel composition (A-3 + farnesane to increase viscosity)

0

10

20

30

40

50

60

70

80

7 8 9 10 11 12 13 14 15 16 17 18 19 20

Gevo ATJ, POSF 11498, "C-1"Sasol IPK, POSF 7629, "CRATCAF C1"POSF 12344, "C-4", 60/40 7629/11498 blend

Iso

pa

raff

ins,

ma

ss%

Carbon number

Figure 23. C-1 and C-4 fuel compositions.

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27

D. Fit for Purpose Properties

Fit-for-properties were measured for the Category C fuels, as for the Category A fuels. The correlations discussed

in the previous section were validated for petroleum fractions, so their relevance to these “constructed” Category C

fuels is questionable – so calculations were not performed for the Category C fuels.

In Figure 24, density as a function of temperature is shown (again) to be linear with temperature over the range of

-40 to +85 C. Two sets of measurements are represented – SwRI (5 to 85 C) and UDRI (-20 and -40 C). For Category

C fuels that are blends, the density was linear with blending, as shown in Figure 25. Thus, even for very asymmetric

mixtures like “C-2”, blending of these hydrocarbons was linear in density. C-1, C-4, and C-5 do not meet the jet fuel

density spec at 15 C (0.77-0.84).

Viscosity versus temperature for the Category C fuels is shown in Figure 26. Most blends fall within experience,

except C-5 (low) and C-3 (high). C-3 was designed to be outside of experience in viscosity –this is illustrated in

Figure 26. Alas, C-5 was designed to be flat-boiling (which it is), but the available ingredients led to a fuel with an

unusually low viscosity, as shown in Figure 26, clouding the combustion results to some extent.

0.7

0.75

0.8

0.85

0.9

-50 0 50 100

10264 A-110325 A-2

10289 A-311498, C-112223, C-212341 C-312344, C-412345, C-5

De

nsity,

g/c

m3

Temperature, C

specification range

Figure 24. Density data for Category C fuels (note - points for C-1 lie underneath C-4 fuel symbols)

Page 28: Reference Jet Fuels for Combustion Testing

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28

0.72

0.74

0.76

0.78

0.8

0.82

0.84

0.86

0.88

0 20 40 60 80 100

Density in 12223; TMB in C14Density in 12345; TMB in C10Density in 12341; farnesane in JP-5 10289

De

nsity,

g/c

m3

Vol% TMB or farnesane

Figure 25. Demonstration of linear blending in “C-2” (POSF 12223), “C-5” (POSF 12345), and “C-3” (POSF

12341).

0

5

10

15

-40 -20 0 20 40 60 80 100

A-1 10264A-2 10325A-3 10289C-1 11498C-2 12223C-3 12341C-4 12344C-5 12345WS min 720WS max 007

D44

5 V

iscosity,

cS

t

Temperature, C

JP-5/high visc

Jet A/Jet A-1

Figure 26. Temperature dependence of viscosity for Category C fuels

Page 29: Reference Jet Fuels for Combustion Testing

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29

Figure 27. Viscosity (-20 C) for several Category C fuels that are “outside of experience”.

Heat capacity (specific heat) data for the Category C test fuels is shown in Figure 28. Many properties seem to

trend with density – heat capacity in this case is not one of them (15 C densities are shown in the legend). It isn’t

clear if the differences among the fuels is real or an artifact of the measurement. The CRC Handbook shows

separate Cp lines for JP-5, Jet A/Jet A-1/JP-8, JP-TS, and JP-4/Jet B, varying by about 0.1 kJ/kg-K at a given

temperature. The CRC Handbook shows a Cp for Jet A/Jet A-1/JP-8 of 2.3 kJ/kg-K at 100 C, consistent with the A-

2 value shown in Figure 28. A recent analysis of specific heat data for jet fuels, alternative fuels, and pure jet fuel-

range hydrocarbons [40] has shown that heat capacity trends more with chemical composition than density. Pure n-

paraffins and iso-paraffins lie above the CRC Handbook jet fuel line, while aromatics lie below. That is broadly

consistent with the data of Figure 28, although the low Cp value for the C-1 fuel (a pure iso-paraffin) is puzzling, as

are the relatively high Cp values for the C-3 fuel (11% aromatics).

Figure 29 shows the surface tension data for the Category C fuels. The data is broadly consistent with the

Category A fuels, although trends with fuel properties are not clear. As shown in Figure 30, surface tension at a

given temperature correlates roughly with density, although there is significant scatter. In Figure 31, vapor pressure

for the Category C test fuels is generally as expected, with the high-viscosity C-3 fuel (based on JP-5) at the low end

and the C-5 fuel on the high end (as expected from its composition).

Page 30: Reference Jet Fuels for Combustion Testing

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30

1.8

2

2.2

2.4

2.6

2.8

0 50 100 150 200

POSF 11498, C-1, 0.759POSF 12223, C-2, 0.782

POSF 12341, C-3, 0.808POSF 12344, C-4, 0.760POSF 12345, C-5, 0.770POSF 10325, A-2, 0.803

He

at C

ap

acity (

Cp

), k

J/k

g-K

Temperature, C

Figure 28. Heat capacity as a function of temperature for Category C fuels (SwRI). 15 C density is shown in

legend.

20

22

24

26

28

30

-20 -10 0 10 20 30 40 50

A-1 10264

A-2 10325

A-3 10289C-1 11498

C-2 12223C-3 12341C-4 12344

C-5 12345

Su

rfa

ce

te

nsio

n,

dyne

/cm

Temperature, C

Figure 29. Surface tension as a function of temperature for Category C fuels (SwRI). Compare Figure 14 for

CRC Handbook data.

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31

20

22

24

26

28

30

0.75 0.76 0.77 0.78 0.79 0.8 0.81 0.82 0.83

-10 C

22 C

Su

rfa

ce

te

nsio

n,

dyne

/cm

Density (15 C) g/cm3

A-3

C-3

C-1

C-4A-1

C-2

A-2C-5

Figure 30 – Surface tension correlation with density

0

1

2

3

4

5

0 50 100 150

C-1 11498

C-2 12223

C-3 12341

C-4 12344

C-5 12345

CRC JP-8

CRC JP-5

Va

po

r p

ressure

, p

sia

Temperature, C

Range in HEFA

Research Report

Figure 31 – Vapor pressure data for Category C fuels

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32

As part of this program, blends of the A-2 Jet A and the C-1 test fuel were made – see Figures 32 to 35. Bulk

properties such as heat of combustion and hydrogen content should be linear with blending – the non-linearity in the

H content is due to scatter in the data/measurement. Density is expected to be linear with blending (as mentioned

earlier) – and is (Figure 34). Viscosity was not expected to be linear with blending – and was not (especially at

lower temperatures – Figure 35).

Over the course of four years, multiple batches of the C-1 fuel were received and multiple measurements were

made of the properties. From the AF Petroleum Agency lab, the heat of combustion measurements were 43.93,

43.90, 43.94, 43.95, 43.77, 44.00, 43.85, 43.74, 43.86, and 44.04 MJ/kg. Measurements at SwRI were 43.82 and

43.95 MJ/kg. So, the mean is 43.90 and the standard deviation is 0.09 MJ/kg. The H content by D7171 (AF) and

D3701 (SwRI) was 15.4, 15.7, 15.2, 15.4, 15.5, 15.2, 15.5, 15.2, 15.2, 15.5, and 15.45 (D3701). The mean was thus

15.4 mass% H, and the standard deviation was 0.17 mass%. Since the C-1 fuel is mostly pentamethyl heptane

(C12H26) isomers, the calculated H content can be estimated as 26(1.008)/(26(1.008)+12(12.011))~15.38 mass%.

So the mean value on H content is apparently relatively accurate, but the standard deviation is higher than desirable.

ASTM D5291 gives 15.34 mass% hydrogen.

43

43.2

43.4

43.6

43.8

44

0 20 40 60 80 100

y = 43.087 + 0.0085882x R= 0.99725

Hea

t o

f co

mb

ustio

n,

MJ/k

g

Vol% C-1 in A-2/C-1 blend

Figure 32 – Heat of combustion as a function of blend ratio for C-1/A-2 blends

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33

13.5

14

14.5

15

15.5

16

0 20 40 60 80 100

y = 13.929 + 0.014864x R= 0.96296

H c

on

ten

t, m

ass %

(D

71

71

)

Vol% C-1 in A-2/C-1 blend

Figure 33 – H content as a function of blend ratio for C-1/A-2 blends

0.76

0.77

0.78

0.79

0.8

0.81

0 20 40 60 80 100

y = 0.803 - 0.00042794x R= 0.99924

De

nsity,

g/m

L

Vol %C-1 in A-2/C-1 blend

Figure 34 – Density as a function of blend ratio for C-1/A-2 blends

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34

4.4

4.5

4.6

4.7

4.8

4.9

5

1.25

1.3

1.35

1.4

1.45

1.5

1.55

0 20 40 60 80 100

Vis

co

sity a

t -2

0 C

, cS

t Vis

co

sity

at 4

0 C

, cS

t

%C-1 in A-2/C-1 blendC-1A-2

Figure 35. Viscosity as a function of blend ratio for C-1/A-2 blends

It was not part of this program, but several sets of blending data for the C-1 (Gevo ATJ fuel) have been obtained

for derived cetane number. As shown in Figure 36, the blending curve of the low cetane “C-1” fuel is not linear

with a number of fuels. A number of different samples of the C-1 fuel have been tested, with DCN ranging from

15.1 to 18.1.

15

20

25

30

35

40

45

50

0 20 40 60 80 100

JP-8"low cetane" JP-5

JP-5 6637JP-5 7382

AS

TM

D6

89

0 D

erive

d C

eta

ne

Nu

mb

er

Volume % ATJ

Figure 36. Derived cetane number for various blends of C-1 fuel with jet fuel

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35

Heat of formation

As mentioned above, the heat of formation might be needed for the Category C fuels, and can be calculated from

the measured hydrogen content and heat of combustion (Table 6). There is more variation in heat of formation

amongst the Category C fuels than the Category A fuels.

Table 6 – Heat of formation calculations

Fuel wt% H

(meas)

SwRI

D3701

H/C molar

(calc from H

content)

Mass heat of

comb, MJ/kg

(AF/SwRI,

meas D4809)

Mass heat

of comb,

kcal/g

Heat of

formation

(calc), cal/g

MW,

GCxGC

Heat of

formation,

kcal/mol

C-1 11498 15.36 2.162 43.88 -10488 -544.04 178 -96.8

C-2 12223 14.42 2.008 43.5 -10397 -438.95 173 -75.9

C-3 12341 14.18 1.969 43.3 -10349 -436.73 180 -78.6

C-4 12344 15.33 2.157 43.8 -10468 -556.91 162 -90.2

C-5 12345 13.96 1.933 42.9 -10253 -486.48 135 -65.7

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36

s

IV. Other “Average” Jet Fuels Distributed

A number of previous “average” fuels have been distributed to researchers over the past 15 years. POSF 6169,

5699, 4177, and 3773 are JP-8 fuels obtained from the active airfield at WPAFB. It is perhaps coincidental that they

are fairly “average”. In contrast, POSF 4658 was created by taking 2000 gallons of each of five different Jet As

(each from a different part of the U.S.) and blending them all together. As can be seen in Table 7, all of these fuels

are similar to the A-2 fuel and are, indeed, pretty average in terms of their properties. GCxGC data is presented in

Appendix D.

Table 7 – Specification data for previous reference fuels

Property Test

Method

Spec

limits

POSF 4658 POSF

6169

POSF 5699 POSF

4177

POSF

3773

PQIS

2012 wt

mean

Density D4052 0.775-0.84 0.806 0.798 0.795 0.814 0.799 0.8022

Flash point, C D93 >38 51 46 50 52 48 47.6

Viscosity, -20

C (cSt)

D445 <8 5.2 4.2 3.8 4.8 4.1 4.399

Aromatics,

vol%

D1319 <25 19 15.7 16.9 16.9 17.2 17.1

Heat of

Combustion,

MJ/kg

D4809 >42.8 43.2

(D3338)

43.5 43.4 43.0 43.1 43.2

H content,

mass% (calc)

D3343 >13.4 14.0 13.7 13.9 13.85

Derived

cetane number

D6890 46.8 47.7 n/a 41.5 49.3 n/a

Smoke pt, mm >19 21.0, 25.0 26.0 26.0 20.0,

22.0

25.0 22.8

Freeze pt, C >-47 (JP-

8)

-48 -50 -51 -58 -49 -51.3

GCxGC est

formula

C11.7H22.6 C11.3H22.1

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37

V. Alternative Jet Fuels A. Introduction

Large alternative fuel programs established in 2006 have led to the certification of 5 alternative “drop-in”

hydrocarbon jet fuels in ASTM D7566 by mid-2016. The properties of these fuels can be found in Research Reports

[11,12,15,18] and other reports [13,14,16,17]. The purpose of this section is to list POSF numbers for common

alternative fuels shipped by the Air Force since 2006. Supplies of many of these fuels still exist.

Often, when fuels are combined, moved, received back from a shipment, or additives are added – a new number

is assigned for a fuel that is chemically identical to a previous number. For example, Sasol IPK was purchased in a

300,000 gallon batch by the AF. When 6000 gallons of that was received by AFRL, it was given the number POSF

5642. A large part of the original 300,000 gallons went to various AF locations for testing – when the excess fuel was

collected at WPAFB by the AF several years later and combined with remaining POSF 5642 at WPAFB, the IPK was

given a new number POSF 7629, although the hydrocarbon composition of the fuel is identical to the original

shipment/batch. Typically a set of jet fuel spec tests is associated with a given POSF ID number. Thus, for example,

the numerous ATJ batches listed below all have a set of (very similar) spec tests so the consistency of the various

batches can be assessed.

(a) ASTM D7566 Annex 1 – Synthetic Paraffinic Kerosene (aka Fischer-Tropsch fuels)

--Sasol IPK (made in South Africa), AF purchase, 2008, same large batch – POSF 5642, 7629, 5959, 5654, 7279,

7280.

--Shell GTL (made in Bintulu Malaysia), AF purchase, 2007, same large batch – POSF 5172, 5729

--Syntroleum GTL (made in Tulsa OK), AF/Army purchases – 2004: POSF 4734 (drums), 2005: POSF 4820 (drums),

2006: POSF 5018 (tanker trucks). Composition very similar between 2004, 2005, 2006 batches

--Rentech GTL – POSF 5698, 7457

(note – these first three fuels make up most of the data in the SPK Research Report [11-12], although the IPK data in

the Research report was largely from Sasol production prior to the batch produced for the Air Force)

(b) ASTM D7566 Annex 2 - Hydroprocessed Esters and Fatty Acids (HEFA) (aka Hydroprocessed Renewable Jet

(HRJ))

--Tallow-based HRJ fuel produced by UOP for AF in 2010 (large batch) – POSF 6308, 6346, 9584, 9585

--Camelina-based HRJ fuel produced by UOP for AF in 2009 – POSF 6152, large batches=POSF 11714, 7720 (not

identical to 6152)

--Mixed-fat-based HRJ produced by Dynamic Fuels/Syntroleum in 2010 (aka “R-8”): large batch – POSF 7272, 7635;

2008 drums: POSF 5469.

(c) ASTM D7566 Annex 5 - Alcohol-to-Jet Synthetic Paraffinic Kerosene

Gevo initial batch - POSF 7504 (1 drum, 2011, lower C16/C12 ratio than all other batches, which are basically

identical)

Subsequent Gevo batches (many were 6000 gallons) - POSF 7695, 7699, 7712, 7788, 7817, 8092, 8158, 8289, 8438,

9641, 10151, 10262, 10373, 11498, 12368, 12384 (2012-2015)

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38

VI. Surrogate Fuels

The focus of this section is much narrower than surrogate fuels in general [19-21]. Here we discuss only two jet

fuel surrogates produced in the hundreds of gallons to compare experimentally to results for the “real” fuel which the

surrogate is supposed to mimic. This builds on the approach developed in a recent MURI [22, 23]. Technically, the

surrogate fuel could be designed to simulate only the combustion chemistry of the parent fuel, but a surrogate which

also mimics the physical properties has the potential to be used to model the fuel throughout the entire

injection/combustion process. One can easily envision a blend of a few hydrocarbons that would match the bulk

physical properties of the fuel being modeled – density, H/C ratio (and sooting), average molecular weight, cetane

number. The difficulty comes with trying to match properties that are dependent upon the multicomponent nature of

the fuel, such as viscosity and (especially) boiling range (as approximated by ASTM D86 distillation). A key

simplification applied is that the boiling range of the entire fuel is being simulated – the boiling range of each class of

hydrocarbons is NOT being simulated – that would require many more surrogate components. Some more complex

surrogates for jet fuels in diesel engines (4 components) [24] and diesel fuel in diesel engines (8-11 components) [25]

have been described. From ongoing testing in NJFCP, it appears that matching the boiling range of individual fractions

is not necessary in the turbulent environment of a gas turbine combustor (as noted above and in other papers at this

meeting, fuels with abnormal boiling distributions in Category C were generally found to burn similarly to

conventional fuels).

These initial surrogates were combination of three hydrocarbons – an n-paraffin, an iso-paraffin, and an aromatic.

The need for including a cyclo-paraffin to match all the major classes of jet fuels is still being debated. In an overall

sense, a surrogate could not consist of just n-paraffins, because the cetane number would be too high and the density

too low. Inclusion of aromatics increases the density and decreases the cetane number, while the effect of adding iso-

paraffins would depend upon the degree of branching. Typically, lightly-branched iso-paraffins make up the largest

hydrocarbon class in conventional jet fuels and have a relatively high cetane number. Highly branched iso-paraffins

have low cetane numbers, as do aromatics.

Alas, the flexibility of surrogate creation is limited by the cost of the ingredients (500 gallons was deemed to be a

good batch size, enabling in use of the surrogate in several larger rigs). This cost issue was recognized early on [19,

20]. In 2016, with jet fuel cost of $2-3/gallon, the cheapest surrogate ingredients were on the order $50/gallon. Some

desirable ingredients were hundreds of dollars/gallon and more. Lightly-branched iso-paraffins in the jet fuel range

are especially expensive. Cyclo-paraffins in the jet fuel range are also currently very high-priced, although some

solvent options may be available.

With that background in mind, two surrogates for the “average” Jet A fuel described earlier (A-2, POSF 10325)

were blended in 2016, as shown in Table 8. The surrogates were 1,3,5 trimethyl benzene and iso-octane blended with

either n-dodecane or n-hexadecane to match H/C ratio, smoke point, and DCN [22,23]. Typically technical grades of

the hydrocarbons were purchased. These surrogates roughly match the DCN, H/C ratio, and smoke point of the

average jet fuel (A-2). The density and average molecular weight of surrogate #1 is somewhat lower than the target

jet fuel. Surrogate #2 increases the MW and density by replacing n-dodecane with n-hexadecane (Table 9). The

ASTM D86 boiling range is shown in Figure 37, and compared to the three Category A fuels. The lower initial boiling

point is due to the compromise of being forced to use iso-octane as the iso-paraffin. Technical grade iso-octane can

be found for under $100/gallon, no doubt because of its use as a component of gasoline primary reference fuels. The

preference was to have iso-dodecane (penta-methyl heptane) as a component [26]– but it was not available in drum

quantities at the time of this paper, even at $100/gallon. Lightly-branched iso-paraffins (e.g., 2-methyl decane) cost

about $1/gram. As discussed in Section 3, 1,3,5 trimethyl benzene has a boiling point of ~160 C, so the replacement

of iso-octane with iso-dodecane would bring the initial boiling point of such a surrogate up into the jet fuel range (IBP

~ 160 C) and increase the MW and density. Note also in Figure 37 that the substitution of dodecane with hexadecane

raises the last 50% of the boiling range significantly – even above typical jet fuels – so an optimized surrogate might

not use n-hexadecane. Some of the specification properties of the surrogates are shown in Table 10.

The combustion behavior of these two surrogates is being assessed and some results may be available in other

papers presented at this meeting [28, 29]. The relationship between the ASTM D86 distillation curve and the actual

fuel evaporation under combustor conditions is uncertain. It was surprising that the three-component nature of the

surrogates was not more evident in the D86 curve, so two other distillation techniques were utilized to characterize

the surrogates. ASTM D7345 “mini-distillation” closely resembled D86, while the ASTM D2887 “simulated

distillation” (GC) technique did more closely resemble the actual boiling points of the three components, as shown in

Figure 37 and 38. The D7345 and D2887 data for the Category A fuels is shown in Appendix C.

Page 39: Reference Jet Fuels for Combustion Testing

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39

Table 8 – Surrogate composition data

Surrogate 1 as

specified, vol %

Surrogate 1 (POSF

12765) as blended

- UDRI GCxGC,

vol %

Surrogate 2 as

specified, vol

%

Surrogate 2

(POSF 12785) as

blended - UDRI

GCxGC, vol %

n-dodecane 59.3 56.7 0

n-hexadecane 0

52.6 50.4

iso-octane 18.4 18.2 25.1 24.9

1,3,5 trimethyl benzene 22.2 22.4 22.2 22.4

iso-C12 (impurity in dodecane)

1.3

iso-C16 (impurity in hexadecane)

1.5

n-C10 (impurity)

0.3

n-C14 (impurity)

0.6

0.3

Table 9 – Surrogate property data (Princeton surrogate calculator)

Surrogate 1 Surrogate 2 Target (A-2 (POSF

10325))

Density ASTM D4052, g/cm3 0.769 0.778 0.803

DCN 50.0 50.6 50.0

Smoke point/TSI 23.8 25.5 25.5

MW 143.2 156.9 160.8

H/C 1.961 1.947 1.961

Table 10 – AFRL surrogate property data on bulk batches

Surrogate 1

(POSF 12765)

Surrogate 2

(POSF 12785)

A-2 (POSF 10325)

D86 distillation, C

IBP 106.7 102.3 159

10% 139 121 176

20% 157 131 184

50% 194 234 205

90% 212 278 244

FBP 226 281 269

ASTM D1319 aromatics, vol% 23 25, 26.8, 25.6 17.0

ASTM D93 flash point, C 24 16 48

ASTM D445 viscosity at -20 C, cSt 2.7 n/a 4.5

ASTM D7171 H content, mass% 14.1 14.305, 14.261 13.8

ASTM D4809 heat of comb., MJ/kg 43.03 42.92 43.1

ASTM D5972 freeze point, C -15.4 -8.1 -51

Molecular formula (GCxGC) C10.3H20.1 C11.2H21.9 C11.4H22.1

ASTM D4052 density, g/ cm3 0.769 0.778 0.803

Page 40: Reference Jet Fuels for Combustion Testing

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40

100

150

200

250

300

0 20 40 60 80 100

POSF 12765 surrogate 1

POSF 12785 surrogate 2POSF 10325 Jet A

POSF 10264 JP-8

POSF 10289 JP-5

AS

TM

D8

6 T

em

pe

ratu

re,

C

% Distilled

Figure 37. ASTM D86 distillation results for surrogates as compared to conventional fuels

50

100

150

200

250

300

0 20 40 60 80 100

12765 D8612765 D7345

12765 D2887

Te

mpe

ratu

re,

C

% distilled

b.p. 216C

59.3 vol% n-C12, 18.4% iso-C8, 22.2% TMB

99 C 165C

Figure 38. ASTM D86/D7345/D2887 distillation results for surrogate fuel #1

Page 41: Reference Jet Fuels for Combustion Testing

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41

50

100

150

200

250

300

0 20 40 60 80 100

12785 D8612785 D7345

12785 D2887

Te

mp

era

ture

, C

% distilled

52.6 vol% n-C16, 25.1% iso-C8, 22.2% TMB

b.p. 287 C 99 C 165C

Figure 39. ASTM D86/D7345/D2887 distillation results for surrogate fuel #2

Note from Table 9 that the freeze point of surrogate 2 is higher than desired for jet fuel, and the viscosity could not be

measured at -20 C because of solidification of the n-hexadecane. However, the density and average MW are close to

the desired values. A third surrogate is being planned with iso-dodecane in place of iso-octane, which should enable

matching DCN, MW, density, smoke point, and viscosity (and perhaps D86 distillation) more effectively than

surrogates #1 and #2.

Page 42: Reference Jet Fuels for Combustion Testing

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42

VII. Conclusion This paper summarizes the various fuels being used as reference fuels for the National Jet Fuel Combustion Program,

as well as other fuels used recently as reference fuels. The paper includes the physical properties of the fuels. The

fuels cover a wide range of combustion-related properties. The fuels are available

to researchers outside of the National Jet Fuel Combustion Program.

Acknowledgments DLA funding support for CRATCAF and NJFCP programs is gratefully acknowledged, as is their assistance with fuel

procurement and shipping.

References

[1] Colket, M., et al, “An Overview of the National Jet Fuels Combustion Program,” AIAA 2016-0177, January

2016.

[2] Edwards, T., Moses, C., Dryer, F., “Evaluation of Combustion Performance of Alternative Aviation Fuels,”

AIAA 2010-7155, July 2010. Also AFRL-RZ-WP-TR-2010-2134 and AFRL-RQ-WP-TR-2013-0223 (limited

distribution).

[3] Coordinating Research Council, “Handbook of Aviation Fuel Properties,” CRC Report 530, 1983/2004.

[4] Hadaller, O. J., & Johnson, J. M., “World Fuel Sampling Program,” Coordinating Research Council Report

647, 2006. (often termed the CRC World Fuel Survey)

[5] Defense Logistics Agency (DLA), “Petroleum Quality Information System (PQIS)”, annual reports.

[6] Riazi, M. R., Characterization and Properties of Petroleum Fractions, ASTM Stock Number: MNL50,

ASTM, West Conshohocken, PA, 2005.

[7] Nelson, W. L., Petroleum Refinery Engineering, McGraw-Hill, New York, 1958.

[8] Maxwell, J. B., Data Book on Hydrocarbons – Application to Process Engineering,” Van Nostrand, NY,

1950.

[9] Lefebvre, A., Gas Turbine Combustion, Hemisphere, NY, 1983. Also Lefebvre, A.H., “Fuel Effects on Gas

Turbine Combustion—Ignition, Stability, and Combustion Efficiency,” Journal of Engineering for Gas Turbines and

Power, Vol. 107, pp. 24-37, 1985. And Lefebvre, A. H., “Fuel Effects on Gas Turbine Combustion,” AFWAL-TR-

83-2004, Jan. 1983.

[10] Striebich,R. C., Shafer, L. M., Adams, R. K., West, Z. J., DeWitt, M. J., Zabarnick, S., “Hydrocarbon Group-

Type Analysis of Petroleum-Derived and Synthetic Fuels Using Two-Dimensional Gas Chromatography,” Energy &

Fuels, Vol. 28, pp. 5696−5706, 2014.

[11] Moses, C., “Comparative Evaluation of Semi-Synthetic Jet Fuels,” final report for CRC Project No. AV-2-04a,

September 2008.

[12] Moses, C., “Comparative Evaluation of Semi-Synthetic Jet Fuels - Addendum: Further Analysis of

Hydrocarbons and Trace Materials To Support Dxxxx,” final report for CRC Project No. AV-2-04a, April 2009.

(DXXXX later became D7566)

[13] Moses, C. A., Stavinoha, L. L., & Roets, P., “Qualification of Sasol Semi-Synthetic Jet A-1 as Commercial

Jet Fuel,” SwRI Report 8531, November 1997.

[14] Rahmes, T. F., Kinder, J. D., Henry, T. M., Crenfeldt, G., LeDuc, G. F., Zombanakis, G. P., Abe, Y., Lambert,

D. M., Lewis, C., Juenger, J. A., Andac, M. G., Reilly, K. R., Holmgren, J. R., McCall, M. J., & Bozzano, A. G.

(2009), “Sustainable Bio-Derived Synthetic Paraffinic Kerosene (Bio-SPK) Jet Fuel Flights and Engine Tests Program

Results,” AIAA 2009-7002, July 2009.

[15] The Boeing Company, UOP, & United States Air Force Research Laboratory. (2011). Evaluation of Bio-

Derived Synthetic Paraffinic Kerosenes (Bio-SPKs). West Conshohocken, PA: ASTM International.

[16] Edwards, T., Shafer, L., Klein, J., “U.S. Air Force Hydroprocessed Renewable Jet (HRJ) Fuel Research,”

AFRL-RQ-WP-TR-2013-0108, July 2012.

[17] Striebich, R., Shafer, L., et al, “Dependence of Fuel Properties During Blending of Iso-paraffinic Kerosene

and Petroleum-Derived jet Fuel,” AFRL-RZ-WP-TR-2009-2034, Nov. 2008.

[18] Edwards, T., Johnston, G., et al, “Evaluation of Alcohol to Jet Synthetic Paraffinic Kerosenes (ATJ-SPK),”

ASTM Research Report, 2016.

[19] Colket, M. B., et al, "Development of an Experimental Database and Kinetic Models for Surrogate Jet Fuels,"

AIAA Paper 2007-770, Jan 2007.

[20] Colket, M. B., et al, “Identification of Target Validation Data for Development of Surrogate Jet Fuels,” AIAA

Paper 2008-972, January 2008.

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[21] Edwards, T., Maurice, L. Q., “Surrogate Mixtures to Represent Complex Aviation and Rocket Fuels,”

Journal of Propulsion and Power, Vol. 17(2), pp. 461-466, 2001.

[22] Dryer, F., Ju, Y., Sung, C.-J., Brezinsky, K., Santoro, R.J., Litzinger, T., and Curran, H., “Generation of

Comprehensive Surrogate Kinetic Models and Validation Databases for Simulating Large Molecular Weight

Hydrocarbon Fuels,” 2007 MURI Topic: Science-Based Design of Fuel-Flexible Chemical Propulsion/Energy

Conversion Systems Contract/Grant No. FA9550-07-1-0515 July 1, 2007 – June 30, 2012.

[23] Dooley, S., Won, S. H., Chaos, M., Heyne, J., Ju, Y., Dryer, F.L., Kumar, K., Sung, C-J., Wang, H.,

Oehlschlaeger, M.A., Santoro, R.J., Litzinger, T., “A jet fuel surrogate formulated by real fuel properties”, Combustion

and Flame Vol. 157 No. 12, 2010, pp. 2333–2339

[24] Kim, D., Martz, J., Violi, A., “A surrogate for emulating the physical and chemical properties of conventional

jet fuel,” Combustion and Flame, Vol. 161, pp. 1489–1498, 2014.

[25] Mueller, C. J., “Methodology for Formulating Diesel Surrogate Fuels with Accurate, Compositional,

Ignition-Quality, and Volatility Characteristics,” Energy & Fuels, Vol. 26, pp. 3284−3303, 2012.

[26] Won, S. H., Haas, F. M., Tekawadeb, A., Kosibab, G., Oehlschlaeger, M., Dooley, S. , Dryer, F. L.,

“Combustion characteristics of C4 iso-alkane oligomers :Experimental characterization of iso-dodecane as a jet fuel

surrogate component,” Combustion and Flame 165 (2016) 137–143.

[27] Bell, D., Heyne, J. S., Won, S. H., Dryer, F. L., Haas, F. M., and Dooley, S., “On the Development of General

Surrogate Composition Calculations for Chemical and Physical Properties,” Submitted to the 55th AIAA Aerospace

Sciences Meeting, Grapevine, TX: American Institute of Aeronautics and Astronautics, 2017.

[28] Stouffer, S. D., Hendershott, T. H., Monfort, J., Diemer, J., Corporan, E., Wrzenski, P., and Caswell, A.,

“Lean Blowout and Ignition Characteristics of Conventional and Surrogate Fuels Measured in a Swirl Stabilized

Combustor,” Submitted to the 55th AIAA Aerospace Sciences Meeting, Grapevine, TX: American Institute of

Aeronautics and Astronautics, 2017.

[29] Chtev, I., Rock, N., Ek, H., Smith, T., Emerson, B., Nobel, D. R., Seitzman, J., Lieuwen, T., Mayhew, E.,

Lee, T., Jiang, N., and Roy, S., “Simultaneous High Speed (5 kHz) Fuel-PLIE, OH-PLIF and Stereo PIV Imaging of

Pressurized Swirl-Stabilized Flames using Liquid Fuels,” Submitted to the 55th AIAA Aerospace Sciences Meeting,

Grapevine, TX: American Institute of Aeronautics and Astronautics, 2017.

[30] Lovestead, T. M., Burger, J. L., Schneider, N., Bruno, T. J., “Comprehensive Assessment of Composition

and Thermochemical Variability of Three Prototype Gas Turbine Fuels by GC/QToF-MS and the Advanced

Distillation-Curve Method as a Basis of Comparison for Novel Fuel Development,” Energy & Fuels, in press (2016) DOI: 10.1021/acs.energyfuels.6b01837 • Publication Date (Web): 26 Oct 2016. [31] Outcalt, S. L., “Compressed Liquid Densities of Three “Reference” Turbine Fuels,” Energy & Fuels, in press

(2016) DOI: 10.1021/acs.energyfuels.6b01820 • Publication Date (Web): 19 Sep 2016.

[32] Edwards, J. T., Hutzler, S., Morris, R. E., Muzzell, P. A., “Tri-Service Jet Fuel Characterization for DOD

Applications; Task 1 Compositional Analysis/Task 2-3 Fit-For-Purpose and Trace Impurity Evaluations,” May 2015.

SwRI Project No. 08.17149.36.100.

[33] Yu, J., Eser, S., “Determination of Critical Properties of Some Jet Fuels. Ind. Eng. Chem. Res. Vol. 34, p.

404, 1995.

[34] Moses, C., “A Review of ASTM D4054 Fit-For-Purpose Results,” Presentation to D02.J0.06 Emerging Fuels

ASTM Aviation Fuels Subcommittee, Ft. Lauderdale, FL, June 24, 2015

[35] Mueller, C. J., et al, “Methodology for Formulating Diesel Surrogate Fuels with Accurate Compositional,

Ignition-Quality, and Volatility Characteristics,” Energy & Fuels, Vol. 26, pp. 3284−3303, 2012.

[36] Riazi, M. R. and Daubert, T. E., “Analytical Correlations Interconvert Distillation Curve Types,” Oil & Gas

Journal, Vol. 84, 1986, August 25, pp. 50–57.

[37] Lenoir, J. M. and Hipkin, H. G., “Measured Enthalpies of Eight Hydrocarbon Fractions,” Journal of Chemical

and Engineering Data, Vol. 18, No. 2, 1973, pp. 195–202.

[38] Edwards, T., ““Kerosene” Fuels for Aerospace Propulsion – Composition and Properties,” AIAA Paper 2002-

3874, July 2002.

[39] Moses, C., Stavinoha, L., Roets, P., “Qualification of Sasol Semi-Synthetic Jet A-1 as Commercial Jet Fuel,

SwRI-8531, Nov. 1997.

[40] Moses, C, “A Review of ASTM D4054 Fit-For-Purpose Results,” Presentation to D02.J0.06 Emerging Fuels,

ASTM Aviation Fuels Subcommittee, Ft. Lauderdale, FL, June 24, 2015

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Appendix A – Tabular Property Data for Category A Fuels

Table A-1 – GCxGC composition (UDRI)

Table A-2 – Miscellaneous compositional measurements (AFPET/SwRI/UDRI)

Table A-3 – Physical/specification properties (SwRI/UDRI)

Table A-4 – Heat Capacity as a function of temperature (SwRI)

Table A-5 – Density, speed of sound, bulk modulus as a function of P for POSF 10325 (SwRI)

Table A-6 – Density, speed of sound, bulk modulus as a function of P for POSF 10264 (SwRI)

Table A-7 – Density, speed of sound, bulk modulus as a function of P for POSF 10289 (SwRI)

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Table A-1 – GCxGC composition (UDRI)

GCxGC SummaryHydrogen content (weight %)

Average Molecular Wt (g/mole)

POSF-10264 JP-8 POSF-10289 JP-5 POSF-10325 Jet AWeight % Volume % Weight % Volume % Weight % Volume %

Aromatics

Alkylbenzenes

benzene (C06) 0.01 0.01 <0.01 <0.01 0.01 0.01

toluene (C07) 0.23 0.21 0.03 0.02 0.16 0.14

C2-benzene (C08) 1.98 1.77 0.41 0.38 1.10 1.00

C3-benzene (C09) 4.17 3.73 1.32 1.24 2.97 2.73

C4-benzene (C10) 2.33 2.09 2.09 1.97 3.32 3.05

C5-benzene (C11) 1.19 1.07 1.98 1.86 2.22 2.03

C6-benzene (C12) 0.66 0.59 1.80 1.70 1.45 1.33

C7-benzene (C13) 0.25 0.22 1.24 1.16 0.73 0.67

C8-benzene (C14) 0.12 0.11 1.05 0.99 0.52 0.48

C9-benzene (C15) 0.06 0.05 0.39 0.37 0.28 0.25

C10+-benzene (C16+) <0.01 <0.01 0.03 0.03 0.15 0.14

Total Alkylbenzenes 11.00 9.85 10.33 9.72 12.90 11.84

Diaromatics (Naphthalenes, Biphenyls, etc.)

diaromatic-C10 0.10 0.08 0.09 0.07 0.22 0.17

diaromatic-C11 0.33 0.25 0.33 0.26 0.66 0.51

diaromatic-C12 0.41 0.32 0.60 0.48 0.86 0.68

diaromatic-C13 0.18 0.14 0.29 0.24 0.43 0.34

diaromatic-C14+ 0.04 0.03 0.04 0.03 0.17 0.14

Total Alkylnaphthalenes 1.06 0.82 1.34 1.09 2.34 1.84

Cycloaromatics (Indans, Tetralins,etc.)

cycloaromatic-C09 0.02 0.02 0.03 0.03 0.02 0.02

cycloaromatic-C10 0.19 0.15 0.57 0.48 0.26 0.21

cycloaromatic-C11 0.37 0.30 1.91 1.66 0.66 0.56

cycloaromatic-C12 0.38 0.32 2.67 2.34 0.89 0.76

cycloaromatic-C13 0.34 0.29 2.27 2.01 0.85 0.73

cycloaromatic-C14 0.16 0.14 1.08 0.96 0.44 0.38

cycloaromatics-C15+ 0.03 0.02 0.14 0.12 0.17 0.15

Total Cycloaromatics 1.49 1.24 8.69 7.60 3.29 2.81

Total Aromatics 13.56 11.91 20.36 18.41 18.53 16.49

Paraffins

iso-Paraffins

C07 & lower -isoparaffins 0.21 0.24 0.02 0.02 0.15 0.18

C08-isoparaffins 0.88 0.97 0.13 0.15 0.44 0.50

C09-isoparaffins 2.59 2.80 0.48 0.54 1.05 1.17

C10-isoparaffins 8.15 8.67 1.66 1.85 4.20 4.57

C11-isoparaffins 8.38 8.73 2.73 2.98 5.70 6.08

C12-isoparaffins 5.41 5.64 3.36 3.67 5.63 6.02

C13-isoparaffins 4.63 4.73 3.57 3.82 4.22 4.41

C14-isoparaffins 3.96 4.00 3.54 3.76 4.20 4.35

C15-isoparaffins 2.28 2.30 2.70 2.85 2.51 2.59

C16-isoparaffins 0.75 0.75 0.65 0.68 1.00 1.03

C17-isoparaffins 0.20 0.20 0.08 0.09 0.39 0.40

C18-isoparaffins 0.03 0.03 <0.01 <0.01 0.11 0.11

C19-isoparaffins <0.01 <0.01 <0.01 <0.01 0.03 0.03

C20-isoparaffins <0.01 <0.01 <0.01 <0.01 0.03 0.03

C21-isoparaffins <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

C22-isoparaffins <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

C23-isoparaffins <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

C24-isoparaffins <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Total iso-Paraffins 37.48 39.07 18.91 20.42 29.69 31.46

n-Paraffins

n-C07 & lower 0.24 0.27 0.02 0.02 0.17 0.20

n-C08 1.11 1.22 0.19 0.22 0.54 0.61

n-C09 2.97 3.20 0.64 0.72 1.42 1.57

n-C10 6.46 6.84 1.41 1.57 3.26 3.53

n-C11 5.22 5.44 2.60 2.85 4.29 4.58

n-C12 3.99 4.11 3.09 3.33 3.74 3.94

n-C13 2.97 3.03 2.50 2.68 2.80 2.93

n-C14 1.97 1.99 1.92 2.04 2.02 2.09

n-C15 0.83 0.83 0.86 0.90 1.03 1.06

n-C16 0.23 0.23 0.11 0.12 0.43 0.44

n-C17 0.06 0.06 0.01 0.01 0.21 0.22

n-C18 <0.01 <0.01 <0.01 <0.01 0.05 0.05

n-C19 <0.01 <0.01 <0.01 <0.01 0.01 0.01

n-C20 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

n-C21 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

n-C22 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

n-C23 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Total n-Paraffins 26.05 27.23 13.35 14.47 19.98 21.23

Cycloparaffins

Monocycloparaffins

C07 & lower monocycloparaffins 0.51 0.51 0.08 0.08 0.36 0.37

C08-monocyclocycloparaffins 1.01 0.99 0.35 0.36 0.78 0.78

C09-monocyclocycloparaffins 3.06 2.98 1.53 1.57 2.30 2.29

C10-monocyclocycloparaffins 4.47 4.22 3.25 3.22 4.11 3.97

C11-monocyclocycloparaffins 3.55 3.44 5.77 5.86 5.43 5.38

C12-monocyclocycloparaffins 2.45 2.36 6.25 6.32 3.73 3.68

C13-monocyclocycloparaffins 2.25 2.15 6.11 6.11 4.19 4.09

C14-monocyclocycloparaffins 1.19 1.14 4.22 4.24 2.19 2.14

C15-monocyclocycloparaffins 0.77 0.74 2.27 2.27 1.33 1.29

C16-monocyclocycloparaffins 0.11 0.10 0.41 0.41 0.42 0.41

C17-monocyclocycloparaffins 0.02 0.02 0.01 0.01 0.18 0.18

C18-monocyclocycloparaffins <0.01 <0.01 <0.01 <0.01 0.04 0.04

C19+-monocyclocycloparaffins <0.01 <0.01 <0.01 <0.01 0.02 0.02

Total Monocycloparaffins 19.41 18.66 30.25 30.44 25.08 24.64

Dicycloparaffins

C08-dicycloparaffins 0.03 0.03 0.03 0.02 0.03 0.03

C09-dicycloparaffins 0.35 0.31 0.46 0.42 0.43 0.39

C10-dicycloparaffins 0.47 0.40 1.04 0.94 0.72 0.63

C11-dicycloparaffins 0.71 0.65 2.84 2.69 1.52 1.41

C12-dicycloparaffins 0.77 0.70 4.33 4.14 1.57 1.47

C13-dicycloparaffins 0.52 0.47 4.53 4.32 1.21 1.12

C14-dicycloparaffins 0.45 0.41 3.14 3.00 0.81 0.76

C15-dicycloparaffins 0.08 0.07 0.63 0.61 0.20 0.19

C16-dicycloparaffins <0.01 <0.01 0.03 0.03 0.04 0.04

C17+-dicycloparaffins <0.01 <0.01 <0.01 <0.01 0.02 0.02

Total Dicycloparaffins 3.39 3.05 17.02 16.17 6.56 6.06

Tricycloparaffins

C10-tricycloparaffins <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

C11-tricycloparaffins 0.11 0.09 0.10 0.09 0.16 0.13

C12-tricycloparaffins <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Total Tricycloparaffins 0.11 0.09 0.10 0.09 0.16 0.13

Total Cycloparaffins 22.91 21.79 47.37 46.70 31.79 30.83

Average Molecular Formula - C 10.8 11.9 11.4

Average Molecular Formula - H 21.7 22.6 22.1

13.7

166

14.0

159

14.4

152

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Table A-2 – Miscellaneous compositional measurements (AFPET/SwRI/UDRI)

Property A-1 (POSF 10264) A-2 (POSF 10325) A-3 (POSF 10289)

ASTM D1319-13 Aromatics, %vol (AFPET) 11.2 17.0 18.3

ASTM D1319-13 Aromatics, %vol (SwRI) 12.3 17.1 19.8

ASTM D5186 Aromatics, %mass (SwRI) 14.4 19.3 20.7

ASTM D6379 Aromatics, %mass (SwRI) 13.7 19.1 21.5

ASTM D6379 (UDRI) 12.6 17.4 19.8

ASTM D7171-05 Hydrogen Content by NMR,

% mass (AFPET)

14.4 13.7, 13.9 13.4

ASTM D3701 H content by NMR, % mass

SwRI

14.26 13.84 13.68

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Table A-3 – Physical/specification properties (SwRI/UDRI/AFPET)

Property A-1 (POSF 10264) A-2 (POSF 10325) A-3 (POSF 10289)

Density, g/L

15 C (AFPET) 0.780 0.803 0.827

5 C (SwRI) 0.7874 0.8106 0.8339

15 C 0.7799 0.8032 0.8268

25 C 0.7724 0.7958 0.8194

35 C 0.7649 0.7884 0.8122

45 C 0.7574 0.7810 0.8048

55 C 0.7498 0.7735 0.7976

65 C 0.7422 0.7660 0.7902

75 C 0.7350 0.7584 0.7828

85 C 0.7286 0.7509 0.7754

Viscosity, cSt

-40 C (AFPET) 6.6 9.2 14.1

-20 C (AFPET) 3.5 4.5 6.5

40 C (SwRI) 1.14 1.31 1.57

100 C (SwRI) 0.61 0.68 0.76

Heat of combustion, MJ/kg (SwRI) D4809 43.239 43.058 42.878

Heat of combustion, MJ/kg (AFPET) 43.1 43.0 43.0

Surface tension, dyne/cm (SwRI) D1331A

-10 C 25.8 28.0 28.4

22 C 23.8 24.8 25.7

40 C 22.8 23.6 24.7

Cetane number, ASTM D613 47.9 47.0 40.4

Ignition Delay (ms), ASTM D6890 4.2 4.3 5.4

Derived cetane number, ASTM D6890 48.8 48.3 39.2

ASTM D86 Distillation (SwRI)

IBP 150.0 159.2 177.9

5% 162.2 173.1 190.2

10% 164.3 176.8 194.2

15 167.4 180.8 197.7

20 171.1 185.4 201.3

30 176.9 191.5 207.9

40 183.0 198.2 213.8

50 189.7 205.4 219.6

60 197.0 212.6 225.3

70 206.5 220.8 231.0

80 218.5 230.9 237.5

90 233.9 244.6 245.8

95 245.0 256.0 252.5

FBP 256.7 270.5 259.5

Flash point 42 48 60

Freeze pt, C -52 -51 -50

Smoke pt, mm 28.5 22 20

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Table A-4 – Heat Capacity as a function of temperature (SwRI)

POSF 10325 POSF 10264 POSF 10289

Table A-5 – Density, speed of sound, bulk modulus as a function of P for POSF 10325 (SwRI)

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Table A-6 – Density, speed of sound, bulk modulus as a function of P for POSF 10264 (SwRI)

Table A-7 – Density, speed of sound, bulk modulus as a function of P for POSF 10289 (SwRI)

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Appendix B – tabular property data for Category C fuels

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Appendix C – Alternative distillation data (see also [30]) As discussed briefly in Section 6, there are a number of alternative distillation techniques that can be used to assess

fuel, in addition to ASTM D86. ASTM D7345 (“Micro Distillation”) generates data similar to D86, but with a

smaller sample, as shown in Figures C-1, C-2, C-3. ASTM D2887 is a gas chromatography method. From D2887:

“Boiling range distributions obtained by this test method are essentially equivalent to those obtained by true boiling

point (TBP) distillation (see Test Method D2892). They are not equivalent to results from low efficiency distillations

such as those obtained with Test Method D86 or D1160.” There is an Annex in D2887 that allows the generation of

data analogous to D86 through correlations. Data shown in Section 6 shows that the D2887 data does more closely

mimic the boiling curve for simple three-component hydrocarbon blends than does ASTM D86.

100

150

200

250

300

350

0 20 40 60 80 100

D86D7345D2887

Te

mpe

ratu

re,

C

% distilled

A-1

Figure C-1 – various distillation results for A-1 (POSF 10264)

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100

150

200

250

300

350

0 20 40 60 80 100

D86D7345D2887

Te

mpe

ratu

re,

C

% distilled

A-2

Figure C-2 – various distillation results for A-2 (POSF 10325)

100

150

200

250

300

350

0 20 40 60 80 100

D86D7345D2887

Te

mpe

ratu

re,

C

% distilled

A-3

Figure C-3 – various distillation results for A-3 (POSF 10289)

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As mentioned earlier, ASTM D86 is not a “true” boiling curve as might be obtained from a distillation column in a refinery – it is

a relatively crude distillation. Riazi ([6], with data from [37]) shows a comparison of a D86 and true boiling curve in Figure C-4

reproduced below.

Figure C-4 – comparison of D86 and true boiling curve.

There are correlation equations for converting D86 curves into true boiling curves ([36] referenced in [6]). The equation is:

TBP = a(ASTM D86)b, where

Vol % a b

0 0.9177 1.0019

10 0.5564 1.0900

30 0.7617 1.0425

50 0.9013 1.0176

70 0.8821 1.0226

90 0.9552 1.0110

95 0.8177 1.0355

This equation is valid for initial boiling points from 20-320 C and final boiling points from 75-400 C, so it includes jet fuels. The

resulting estimate for true boiling point resembles the ASTM D2887 data, and does behave similarly to Figure C-4, as shown in

Figure C-5. So, if one needed true boiling point data for some type of combustion modeling, one could use ASTM D2887 data in

place of the Reference 36 calculation, if desired. This appears to validate the point seen in Figure 6-2 and 6-3, where the D2887

data appears to closely mimic the actual boiling point for simple three-component mixtures.

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100

150

200

250

300

350

0 20 40 60 80 100

D86D2887D7345TBP calc [36]

Te

mpe

ratu

re,

C

% distilled

A-2

Figure C-5 – addition of estimated true boiling point calculated point to A-2 (POSF 10325) distillation data.

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Appendix D – GCxGC for previous reference fuels (Section IV)

6169 4658 5699 3773 4177

Weight % Weight

% Weight % Weight % Weight %

Aromatics

Alkylbenzenes

benzene (C06) 0.02 <0.01 <0.01 0.00 0.00

toluene (C07) 0.14 0.16 0.08 0.06 0.10

C2-benzene (C08) 0.81 0.78 0.63 0.69 0.64

C3-benzene (C09) 2.69 2.24 3.21 3.64 1.82

C4-benzene (C10) 3.22 3.02 3.91 3.48 2.88

C5-benzene (C11) 2.32 2.48 2.63 2.31 2.79

C6-benzene (C12) 1.69 1.93 1.80 4.99 6.38

C7-benzene (C13) 1.01 1.19 1.08

C8-benzene (C14) 0.61 0.89 0.63

C9+-benzene (C15+) 0.36 1.00 0.22

C10+-benzene (C16+) 0.06

Total Alkylbenzenes 12.87 13.69 14.25 15.17 14.60

Alkylnaphthalenes

C0-naphthalene (C10) 0.16 0.12 0.07 0.15 0.16

C1-naphthalene (C11) 0.47 0.42 0.27 0.61 0.52

C2-naphthalene (C12) 0.64 0.60 0.40 1.59 0.83

C3-naphthalene (C13) 0.30 0.40 0.16

C4+-naphthalene (C14+) 0.18 0.23 0.05

Total Alkylnaphthalenes 1.76 1.76 0.96 2.35 1.51

Cycloaromatics (Indans, Tetralins,etc.)

cycloaromatic-C09 0.05 0.04 0.06

cycloaromatic-C10 0.41 0.43 0.45

cycloaromatic-C11 0.83 1.13 1.08

cycloaromatic-C12 1.08 1.63 1.40

cycloaromatic-C13 1.10 1.45 1.04

cycloaromatic-C14 0.40 0.71 0.33

cycloaromatics-C15+ 0.14 0.41 0.08

Total Cycloaromatics 4.02 5.79 4.43 2.47 4.31

Total Aromatics 18.65 21.25 19.64 19.99 20.42

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6169 4658 5699 3773 4177

Paraffins

iso-Paraffins

C07 and lower-iso 0.21 0.23 0.17 0.14 0.20

C08-isoparaffins 0.45 0.56 0.44 0.35 0.32

C09-isoparaffins 1.88 1.08 1.51 1.68 0.83

C10-isoparaffins 5.40 3.59 5.92 6.33 3.43

C11-isoparaffins 7.04 5.12 7.01 6.86 4.97

C12-isoparaffins 5.68 5.31 5.55 5.95 5.76

C13-isoparaffins 4.88 5.25 5.00 4.46 5.47

C14-isoparaffins 3.93 4.44 3.83 3.38 2.97

C15-isoparaffins 2.38 3.10 2.10 1.85 1.20

C16-isoparaffins 0.82 1.66 0.59 0.68 0.43

C17-isoparaffins 0.29 0.69 0.33 0.33 0.57

C18-isoparaffins 0.09 0.19 0.04

C19-isoparaffins 0.03 0.08 0.02

C20-isoparaffins <0.01 0.02 <0.01

C21-isoparaffins <0.01 <0.01 <0.01

C22-isoparaffins <0.01 <0.01 <0.01

C23-isoparaffins <0.01 <0.01 <0.01

C24-isoparaffins <0.01 <0.01 <0.01

Total iso-Paraffins 33.11 31.34 32.53 32.00 26.14

n-Paraffins

n-C07 0.13 0.15 0.13 0.06 0.07

n-C08 0.55 0.54 0.52 0.39 0.32

n-C09 1.84 1.14 1.94 2.14 0.71

n-C10 4.26 2.55 5.30 3.66 1.76

n-C11 4.53 3.62 5.20 4.01 3.02

n-C12 4.06 3.70 4.48 3.32 2.92

n-C13 3.07 2.86 3.44 2.74 2.13

n-C14 2.09 2.17 2.16 2.00 1.08

n-C15 0.89 1.28 0.74 1.05 0.42

n-C16 0.30 0.61 <0.01 0.34 0.18

n-C17 0.11 0.27 0.06

n-C18 0.03 0.05 0.02

n-C19 <0.01 0.02 <0.01

n-C20 <0.01 <0.01 <0.01

n-C21 <0.01 <0.01 <0.01

n-C22 <0.01 <0.01 <0.01

n-C23 <0.01 <0.01 <0.01

Total n-Paraffins 21.87 19.00 24.02 19.72 12.62

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American Institute of Aeronautics and Astronautics

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6169 4658 5699 3773 4177

Cycloparaffins

Monocycloparaffins

C1-monocyclo (C07) 0.18 0.20 0.14

C2-monocyclo (C08) 0.55 0.69 0.39

C3-monocyclo (C09) 1.79 1.67 1.45

C4-monocyclo (C10) 3.64 3.26 4.00

C5-monocyclo (C11) 4.17 4.11 4.34

C6-monocyclo (C12 3.75 4.07 3.96

C7-monocyclo (C13) 3.70 3.65 3.01

C8-monocyclo (C14) 1.74 2.43 1.84

C9-monocyclo (C15) 0.77 1.55 0.72

C10-monocyclo (C16) 0.23 0.64 0.14

C11-monocyclo (C17) 0.07 0.28 0.04

C12-monocyclo (C18) 0.01 0.06 <0.01

C13+-monocyclo (C19+) 0.01 0.03 0.01

Total Monocyclopar. 20.63 22.64 20.05 22.23 28.48

Dicycloparaffins

C08-dicycloparaffins 0.03 0.02 0.02

C09-dicycloparaffins 0.23 0.29 0.22

C10-dicycloparaffins 0.70 0.43 0.49

C11-dicycloparaffins 1.33 1.26 0.95

C12-dicycloparaffins 1.30 1.22 0.81

C13-dicycloparaffins 1.22 1.42 0.77

C14-dicycloparaffins 0.65 0.82 0.37

C15+-dicycloparaffins 0.13 0.21 0.06

C16-dicycloparaffins 0.02 <0.01

C17+-dicycloparaffins 0.03 <0.01

Total Dicycloparaffins 5.59 5.73 3.71 6.06 12.34

Tricycloparaffins

C10-tricycloparaffins 0.02 <0.01 <0.01

C11-tricycloparaffins 0.11 0.05 0.05

C12-tricycloparaffins 0.03 <0.01 <0.01

Total Tricycloparaffins 0.16 0.05 0.05

Total Cycloparaffins 26.38 28.42 23.81 28.29 40.82

Average Molecular Formula - C 11.69 11.3

Average Molecular Formula - H 22.62 22.1