modelling of unsteady combustion in low emission … · modelling of unsteady combustion in low...

MUSCLES

Modelling of UnSteady Combustion in Low Emission Systems

G4RD-CT-2002-00644

Work package 2 Prediction of unsteady reacting flow and validation

Task 2.2

Radiation - Vaporisation interaction

Deliverable Report 2.12

Measurements for Different Heat Loads

Responsible Partner Instituto Superior Técnico Av. Rovisco Pais 1049-001 Lisboa Portugal

Authors Isabel S. Carvalho M. Costa E. C. Fernades

- May 2003 -

I.S.T. Lisbon MUSCLES / May 2003

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Table of Contents

Contents 1 1. Introduction 2 2. Experimental Set-Up 2

2.1. Test Rig - Present Configuration 2 2.2. Preliminary Tests 6

3. Conclusions 11

Final Note 13

Cited References 14

Annex

A1. Composition of JP4 and JP8 15

A2. Tables of Contents – related to TOC files 18


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1. Introduction The present report describes the work carried out by IST since the last MUSCLES meeting in December 2002, held in Naples, and follows the 6 months Deliverables Report, namely: Deliverable Report 2.10 - Design and Manufacture of the Experimental Apparatus Deliverable Report 2.11 - Relevant Studies on Droplet Vaporization: References and

Initial Survey The present report mainly addresses the design and manufacture of the experimental test rig and the related initial tests (Milestone M2.2). A detailed description of the experimental set-up and the measurement techniques is provided. Also, and following the initial literature survey, other relevant related studies are mentioned, which will be used to assess the present experimental data. 2. Experimental Set-Up 2.1. Test Rig - Present Configuration A schematic diagram of the experimental test rig, in its present configuration, is provided in Figure 1. The experimental set-up consists of a vertical tube into which the droplets are injected vertically downwards. The air is electrically heated by four electrical resistances (2 kW each) located in the inner wall of the cylindrical tube (radiator), which is composed of two symmetrical half shells at a distance of 35 mm one from each other. The radiator has an inner diameter of 200 mm and is 1 m long. Different temperatures can be obtained using the voltage controller (variable resistance). Details on the most relevant parts of the experimental set-up are provided in Figures 2 and 3. Figures 2a and 3a illustrate the inner wall of the radiator and the layout of the heating coils, while Figures 2b and 3b provide a view of the outer wall and the optical and thermocouple movable access slot. Figures 2c and 3c show the cooling cone at the top entrance of the heated tube, which ensures the required droplet inlet/initial conditions. Figure 3c also shows the needle and needle support. The liquid flow is controlled by a pump/syringe system, which is illustrated in Figure 4.


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Seringe(water)

Pump

Needle

Radiator(8 kW)

Water-cooled separator

Variable resistance

Multimeter(V, I)

Equipment support

Thermocouple type R

to DAQ

Seringe(water)

Pump

Needle

Radiator(8 kW)

Water-cooled separator

Variable resistance

Multimeter(V, I)

Equipment support

Thermocouple type R

to DAQ

Figure 1. Schematic diagram of the experimental set-up


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a) b) c) Figure 2. Experimental set-up: views and details


a) b)

c) Figure 3. Experimental set-up: a) and b) Different views of the radiator tube;

c) Cooling cone

Figure 4. Pump/Syringe System for Liquid Flow Feeding System

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2.2. Preliminary Tests In this first stage, the test rig was tested and the temperature distribution inside the cylindrical tube was measured. The main objective is to test for possible asymmetries and to characterize the temperature distributions for different heat loads. In a typical experiment, the temperature and velocity of the air stream in the test section will be selected by adjusting the power inputs to the heater and the movable slots at the lower end of the tube. Due to the large thermal inertia of the system, the process takes approximately one hour to be completed, i.e., to achieve uniform steady state conditions inside the testing tube. Temperature measurements were obtained with fine bare-wire thermocouples made of Platinum - Platinum/13% Rhodium wires with a diameter of 100µm, welded by a condenser electrical discharge method. The thermocouple is mounted on a fork-shape support, which is also made of Pt-Pt/13%Rh, and has a nominal diameter of 0.5mm. These wires are then inserted into an alumina tube and radially inserted in the chamber. The probe is mounted on a three-dimensional/3D moving support, with Mitutoyo precision screws, allowing it to move with a spatial precision of +/- 0.1mm. The thermocouple was traversed radially inward through the chamber in steps of 5mm to 1mm. The signal was differentially amplified (x 300) by a low-noise low-drift preamplifier, before entering the acquisition system. The error in statistical processing is less than 1%, due to the very high population size of the order of 10x214 data points. The acquisition board used throughout this work to acquire and process temperature signals was a Data Translation-Fulcrum model DT-3809. This board combines a TMS320C40 DSP (Digital Signal Processor) from Texas Instruments with the acquisition module which comprises an A/D SSHS (Analogue-to-Digital Simultaneous Sample and Hold System), D/A (Digital-to-Analogue), DIO (Digital Input-Output) and Clock/Trigger Services, and is therefore a data acquisition system optimised for real-time synchronous mixed-signal measurement and processing. Figures 5 and 6 show sample results for maximum heat power and the inlet air controller (movable slots at the lower end of the tube) totally closed, near the top of the test tube, at X = 15 and 85 mm, respectively. In the preliminary tests a syringe was used in the place of a droplet generator. The liquid (water) feed line from the syringe pump to the droplet suspension tube (needle) is protected from the high temperature air stream by a housing and an elbow. The syringe pump is a high precision positive displacement injector, which through a combination of different syringe sizes and a variable speed motor can supply distinct flow rates.


400

450

500

550

600

650

700

750

-60 -40 -20 0 20 40 60

Radial Distance [mm]

Tem

pera

ture

[K]

Figure 5. Temperature radial profile: X = 15 mm

600

650

700

750

800

850

900

-60 -40 -20 0 20 40 60

Radial Distance [mm]

Tem

pera

ture

[K]

Figure 6. Temperature radial profile: X = 85 mm

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Droplet measurements were performed by means of a laser light beam (Laser Spectra-Physics-Stabilité-2017 with 2W/514.5nm), positioned normal to the flow in a 180° arrangement with a CCD Camera, as shown in Figure 7. Image acquisition was performed using a high-speed Digital CCD camera (Kodak Motion Corder Analyzer- SR-Series), enabling flow patterns to be recorded with a sampling rate up to 10 000 images per second and selectable electronic exposure gating from 1/30sec to 1/20000 sec. The front lens is a Nikkor 25mm with apertures from f/1.4-5.6. Presently the effort is directed towards the optimisation of the test rig operating conditions, optical system and image processing. Preliminary results were also obtained to assess the influence on the droplet diameter when exposed to different heat load (non-isothermal conditions). Figure 8 shows some sample results of the droplets inside the tube in isothermal and maximum heat load conditions.

LASERLASER

Laser Lens

Screen

Liquid

CCD Camera

PC

TV

LASERLASERLASERLASER

Laser Lens

Screen

Liquid

CCD Camera

PC

TV

Figure 7. Schematic Diagram of the Visualisation System

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Figure 8. Droplet visualization at X = 785 mm: a) isothermal flow conditions;

b) maximum heat load A literature survey is being performed following the first one included in the first Project Report. Presently, the objective is the gathering and analysis of existing data regarding previous experimental work and related data on droplet vaporisation of different liquid fuels, namely n-heptane, n-decane, n-dodecane and kerosene. As mentioned before, this survey also includes the analysis on the type of liquids fuels used, test-rig geometry identification, experimental test conditions (temperature, pressure, initial droplet diameter, etc.) among others. N-heptane was selected as the starting fuel due to its interest as an idealized model fuel for diesel and other engine-combustion applications. As it is, more experimental results are available concerning n-heptane, hence allowing the test and calibration of the present test rig. Tables A1 and A2 (Annex 1) present the different components of JP-4 and JP-8 and their properties. Presently, the liquid fuels to be tested are already available at the IST, and are referred in Table 1.

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Table 1 – Fuel Properties

Fuel Formula Mass Weight (kg/kmol)

HHV (kJ/kg)

LHV (kJ/kg)

Boiling Point

(ºC)

hfg (kJ/kg)

ρliq

(kg/m3)

n-heptane C7H16 100.203 48456 44926 98.4 316 684

n-decane C10H22 142.284 48020 44602 174.1 277 730

n-dodecane C12H26 170.337 47841 44467 216.3 256 749

HHV and LHV – Rossini, F.D., et al., Selected Values of Physical and Thermodynamic Properties of Hydrocarbons and Related Compounds, Carnagie Press, Pittsburgh, PA, 1953.

Boiling Point – Weast, R.C. (ed.), Handbook of Chemistry and Physics, 56th Ed., CRC Press, Cleveland, OH, 1976.

hfg and ρliq – Obert, E.F., Internal Combustion Engines and Air Pollution, Harper & Row, New York, 1973.


3. Conclusions

The work performed during the first year is summarized in Tables 2 and 3.

The work is estimated to be approximetly 2 months late, in accordance with the initialy proposed Workplan. Nevertheless, no further delays are envisaged and the proposed work should be on schedule by the end of the year (18 months meeting).

Table 2. Proposed work plan

Task Year 1 Year 2 Year 3

1 – Theoretical and experimental survey

2 – Design of the experiments and test rig set-up

3 – Experimental measurements

4 – Results Evaluation and Experimental Data Base

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Table 3. Project Deliverables

No. Date Delivered Nature of Deliverable and Brief Description

D2.10 M06 Dec 2002 Design and Manufacture of the Experimental Apparatus

D2.11 M06 Dec 2002 Report on Related Relevant Studies on Droplet Vaporisation

D2.12 M12 Late Report on Measurements for Different Heat Loads

D2.13 M18 Report on Measurements for Different Initial Diameters

D2.14 M24 Report on Measurements for Different Temperatures

D2.15 M30 Report on Measurements for Different Concentration Ratios

D2.16 M36 Final Report and Data Base of the Experimental Results in Electronic Format


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FINAL NOTE The Journal “database”, which includes the Table of Contents from several scientific journals in this field, is presently updated and already available to use at the project website. As agreed, at the 6 months meeting is Naples, it will be constantly updated during the MUSCLES project. The related READ ME file is presented in the Annex 2.


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Cited References Clewell III, H.J. (1980). Evaporation and Groundfall of JP-4 Jet Fuel Jettisoned by USAF Aircrfat. ESL-TR-80-56, Final Report, Air Force Engng. Service Center, Tyndal AFB, FL (in, Runge, T., Teske, M. and Polymeropoulos, C.E. (1998). Low-Temperature Vaporization of JP-4 and JP-8 Fuel Droplets. Atomization and Sprays, 8(1), pp.25-44). Clewell II, H.J. (1983). Ground Contamination by Fuel Jettisoned from Aircraft. J. Aircrfat, vol.20, pp.382-384 (in, Runge, T., Teske, M. and Polymeropoulos, C.E. (1998). Low-Temperature Vaporization of JP-4 and JP-8 Fuel Droplets. Atomization and Sprays, 8(1), pp.25-44).


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ANNEX A1


Table A1 – Composition of JP-4 (Clewell, 1980)

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Table A2 – Compositions of JP-8 (Clewell, 1983)

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ANNEX A2


TABLE OF CONTENTS – TOC FILES

UP DATE: MAY 2003

The TOC files are named with the Journal title followed by the extension TOC. These files

include the Table of Contents for each Journal. The issues included for the different

Journals are listed in the table below.

JOURNAL

SINCE

UP TO

AIAA JOURNAL OF PROPULSION AND POWER

Vol.13 (1), January 1997 Vol.19 (2), March 2003

ATOMIZATION AND SPRAYS

Vol.1 (1), 1991 Vol.12 (5&6), 2002

COMBUSTION AND FLAME

Vol.100 (1-2), 1995 Vol.132 (4), May 2003

COMBUSTION SCIENCE AND TECHNOLOGY

Vol.174 (1), January 2002 Vol.175 (5), Jan./Feb. 2003

EXPERIMENTAL THERMAL AND FLUID SCIENCE

Vol.10 (1), 1995 Vol.27 (5), 2003

FUEL

Vol.74 (1), 1995 Vol.82 (11), July 2003

INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW

Vol.16 (1), 1995

Vol.24 (3), 2003

INTERNATIONAL JOURNAL HEAT AND MASS TRANSFER

Vol.38 (1), 1995 Vol.46 (14), 2003

INTERNATIONAL JOURNAL MULTIPHASE FLOW

Vol.21 (1), 1995 Vol.29 (4), 2003

JOURNAL OF AEROSOL SCIENCE

Vol.28 (S1), 1997 Vol.34 (5), 2003

PROGRESS IN ENERGY AND COMBUSTION SCIENCE

Vol.21 (1), 1995 Vol.29 (2), 2003

In each TOC file, clicking on the provided URL will provide access to the original Table of

Contents. For example:

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AIAA JOURNAL OF PROPULSION AND POWER Click on the given URL and then… click on “Journal of Propulsion and Power”

ATOMIZATION AND SPRAYS Click on the given URL and then… chose your volume and issue.

At the present moment only the Table of contents for years 2001 and 2002 can be

accessed online. The previous volumes and issues (since 1991) are not available

anymore. Nevertheless, as the present TOC document has been initiated in July 2002, all

the tables of contents are listed in the related TOC file (ATOMIZATION AND

SPRAYS_TOC.doc).

COMBUSTION AND FLAME EXPERIMENTAL THERMAL AND FLUID SCIENCE INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER INTERNATIONAL JOURNAL OF MULTIPHASE FLOW Click on the given URL and then… click (on the left bar) on “Contents Services - Tables of

Contents”

FUEL JOURNAL OF AEROSOL SCIENCE PROGRESS IN ENERGY AND COMBUSTION SCIENCE Click on the given URL and then… click (on the left bar) on “Tables of Contents and

Abstracts”.

COMBUSTION SCIENCE AND TECHNOLOGY Click on the given URL and then… click on “Table of Contents”

The websites can also be directly accessed through:

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JOURNAL

URL

AIAA JOURNAL OF PROPULSION AND POWER

http://www.aiaa.org/Research/index.hfm?res=13


http://www.begellhouse.com/journals/6a7c7e10642258cchtml

COMBUSTION AND FLAME COMBUSTION SCIENCE AND TECHNOLOGY

http://www.tandf.co.uk/journals/titles/00102202.html

EXPERIMENTAL THERMAL AND FLUID SCIENCE FUEL http://www.elsevier.nl/inca/publications/store/3/0/4/2/0/


INTERNATIONAL JOURNAL HEAT AND MASS TRANSFER

http://www.elsevier.nl/inca/publications/store/2/1/0/

INTERNATIONAL JOURNAL OF MULTIPHASE FLOW






http://www.elsevier.nl/inca/publications/store/5/0/5/7/3/6/



Alternatively, the different TOC files can be accessed from the present file by clicking on

the links given in the table below.

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http://www.aiaa.org/Research/index.hfm?res=13

http://www.begellhouse.com/journals/6a7c7e10642258cc.html

http://www.begellhouse.com/journals/6a7c7e10642258cc.html

http://www.tandf.co.uk/journals/titles/00102202.html

http://www.elsevier.nl/inca/publications/store/3/0/4/2/0/






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JOURNAL

TOC FILE

AIAA JOURNAL PROPULSION AND POWER

AIAA JOURNAL OF PROPULSION AND POWER_TOC.doc


ATOMIZATION AND SPRAYS_TOC.doc

COMBUSTION AND FLAME

COMBUSTION AND FLAME_TOC.doc

COMBUSTION SCIENCE AND TECHNOLOGY

COMBUSTION SCIENCE AND TECHNOLOGY_TOC.doc

EXPERIMENTAL THERMAL AND FLUID SCIENCE

EXPERIMENTAL THERMAL AND FLUID SCIENCE_TOC.doc

FUEL

FUEL_TOC.doc


INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW_TOC.doc

INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSF

INTERNATIONAL JOURNAL OF HEAT AND MATRANSFER_TOC.doc

INTERNATIONAL JOURNAL MULTIPHASE FLOW

INTERNATIONAL JOURNAL OF MULTIPHAFLOW_TOC.doc


JOURNAL OF AEROSOL SCIENCE_TOC.doc


PROGRESS IN ENERGY AND COMBUSTSCIENCE_TOC.doc

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