d6.4 report and library on surface chemistry

SACOMAR

Technologies for Safe and Controlled Martian Entry

SPA.2010.3.2-04

EU-Russia Cooperation for Strengthening Space Foundations (SICA)

Re-entry Technologies and Tools

Theme 9 - Space Activity 9.3 - Cross-Cutting-Activities Area 9.3.2 - International Cooperation

Deliverable Reference Number: D6.4

Deliverable Title: Report and library on surface chemistry

Due date of deliverable: 31st December 2011

Actual submission date: 16th January 2012

Start date of project: 20th January 2011

Duration: 18 months

Organization name of lead contractor for this deliverable: IPM

Revision 2: Final version of the report

APPROVAL

Project co-funded by the European Commission within the 7th Framework Programme

Dissemination Level

PU Public X

PP Restricted to other programme participants (including the Commission Services)

RE Restricted to a group specified by the consortium (including the Commission Services)

CO Confidential, only for members of the consortium (including the Commission Services)

Title

Report and library on surface chemistry

issue

1

revision

1

Author(s)

A. Kolesnikov, S. Vasil’evskii, A. Levitin, A. Gordeev

26-01-2012

Approved by

Deputy Director of IPM S. Surzhikov

Date

26-01-2012

SACOMAR Deliverable No. D6.4 Report and library on surface chemistry - i

Table of Contents

1 Executive summary 1 1.1 Scope of the deliverable 1

1.2 Results 1

1.3 Specific highlights 1

1.4 Forms of integration within the work package and with other WPs 2

1.5 Problem areas 2

2 Introduction 2

3 Mars entry environment 4

4 Gas/Surface reactions at cold wall test conditions 5

5 IPM approach for predicting surface catalycity 7

6 Demonstration of heating effect of surface recombination 8

7 IPM model of surface catalysis in CO2 mixture 9

8 Boundary conditions for diffusion equations of Goulard’s type 10

9 Previous IPM data for quartz and supporting literature results 10

10 Role of standard high catalytic surface in predicting effective catalycity of materials 14

11 Determination of efficient recombination coefficients for metals and quartz at specified CO2 tests conditions using IPM approach 14

12 Two models of surface catalysis adapted to the EXOMARS entry conditions 22

12.1 Two-parameter model based on Eley-Rideal mechanism 22

12.2 Single-parameter model based on Langmuir-Hinshelwood mechanism - atoms diffusion on high temperature surface 22

13 Electronic library with published experimental data on surface catalytic properties for different materials - GwLibrary 23

14 Conclusions 28

15 References 29

SACOMAR Deliverable No. D6.4 Report and library on surface chemistry - ii

List of figures

Figure 1: Relative stagnation point heat flux vs catalytic recombination rate Kw [1]. 1 – metals, 2 – oxides, 3 – glass. 2

Figure 2: Laminar convective heat flux along the Mars Pathfinder at base line at peak heating point [50]. 5

Figure 3: Schematic of Eley-Rideal (a) and Langmuir-Hinshelwood (b) atom-atom recombination [61]. 6

Figure 4: Stationary water-cooled calorimeter with massive silver surface [62]. 6

Figure 5: Time history of silver surface oxidation in CO2 plasma flow for the test regime Ptc = 76 hPa, Nap = 45 kW [62]. 7

Figure 6: Stagnation point heat flux to different heat flux probes in subsonic CO2 flow at the pressure 80 hPa vs generator anode power [62]. 8

Figure 7: Schematic of O-atom surface recombination according to Eley-Rideal mechanism [39]. 9

Figure 8: Heart flux envelope for pure oxygen flow at h=19.6 MJ/kg, p=100 hPa [56]. 11

Figure 9: Heart flux envelope for CO2 flow at h=21.1 MJ/kg, p=100 hPa [56]. 11

Figure 10: Comparison of data for average efficiency w [57] 12

Figure 11: Relative O-atom concentration along diffusion tube side arm, p=41.5 Pa [64]. 13

Figure 12: Relative CO concentration along diffusion side arm at 295 K, p=49.6 – 50.7 Pa [64]. 13

Figure 13: Heat flux envelope and data for testing materials at the CO2 test regime: P=80 hPa, Nap=40.4 kW, Z=40 mm, he=14.0 MJ/kg. 15

Figure 14: Heat flux envelope and data for testing materials at the CO2 test regime: P=80 hPa, Nap=34 kW, Z=40 mm, he=8.8 MJ/kg. 16



Figure 17: Data on w for quartz surface obtained in CO2 and pure oxygen flows. 20

Figure 18: Notations used in Fig. 17. 21

List of tables

Table 1: Test regimes and measured heat fluxes to the tested materials. 15

Table 2: Effective probability w determined for the tested materials (copper, stainless steel, quartz) for the four test regimes. 19

Table 3: Published experimental data on surface catalytic properties for different materials from GwLibrary. 24

SACOMAR Deliverable No. D6.4 Report and library on surface chemistry - iii

Nomenclature Ci - Mass fraction of the i-th species

Ji [kg/(sm2)] Mass diffusion flux of the i-th species

h [MJ/kg] Enthalpy

Kw [m/s] Catalytic recombination rate

M - Mach number

m [kg/kmol] Molar mass of gas mixture

Nap [kW] Anode power of RF-generator

Npl [kW] Power input in plasma

p [Pa] Pressure

Ptc [Pa] Pressure in test chamber

qw [W/cm2] Stagnation point heat flux

RA [J/mol/K] Universal gas constant

Re - Reynolds number

T [K] Temperature

xi - Molar fraction of the i-th species

Z [m] Distance from discharge channel exit to the model

w - Catalytic efficiency of surface recombination reactions

[kg/m3] Density

Subscripts 0 Stagnation condition

Free stream condition

e External edge of boundary layer

w Surface of testing model

Acronyms

CFD Computational Fluid Dynamics

DLR German Aerospace Centre

ICP Inductively coupled plasma

IPG-4 RF-plasmatron of IPM, Moscow

IPM Institute for Problems in Mechanics

LIF Laser-induced fluorescence

MESOX Oxidation Solar Test Facility, PROMES-CNRS, France

TALIF Two-photon absorption laser-induced fluorescence

TPM Thermal protection material

TPS Thermal protection system

RF Radio-frequency

WP Work Package

SACOMAR Deliverable No. D6.4 Report and library on surface chemistry - Page 1 of 34

1 Executive summary

1.1 Scope of the deliverable

Gather appropriate information for surface catalycity

Gather appropriate information for diffusion on the surface

Comparative analysis all of the heat transfer data and determination catalycity of different surfaces (metals and quartz)

Development of electronic library on published experimental data for surface catalycity of different materials

1.2 Results

A. Review of literature related to the methods of determination of catalytic recombination rates and appropriate data are presented.

B. Effective recombination coefficients of O-atoms and CO-molecules (w) on water-cooled copper, stainless steel and quartz probe in the four selected subsonic high-enthalpy carbon dioxide flow regimes are determined using IPM standard methodology.

C. Novel two-parameter model of O-atoms and CO-molecules surface recombination based on Eley-Rideal mechanism is proposed.

D. Model of O-atoms surface recombination based on Langmuir-Hinshelwood mechanism (atoms diffusion) is discussed.

E. Published and new experimental data on surface catalytic properties for different testing materials - metals (silver, copper, stainless steel), quartz, SiO2-based coatings, and some other materials - obtained in the flows that contain O atoms (pure oxygen, CO2, air) are analyzed and collected in the electronic library (GwLibrary). At present, GwLibrary contains 169 lines, each line provides the information on surface catalytic properties for one of materials, obtained from one reference. In total, 30 references (papers, proceedings, reports, sections of books) were used to collect the data. GwLibrary presents the following surface catalytic properties: Gw (or ) - recombination coefficient for single species; Beta (or β) - chemical energy accommodation coefficient for single species; Gweff (or ’ = β) - effective recombination coefficient, including energy accommodation effect, for single species, or for the group of species.

F. GwLibrary in fact is the electronic database. Appropriate DBMS (database management system) was developed to provide the access to GwLibrary via Internet Web-site. GwLibrary is available at http://plasmalab.ipmnet.ru/GwLibrary/ The shortened version of GwLibrary is presented as Table 3 in this report.

1.3 Specific highlights

Special attention is paid to selection of the standard high-catalytic material. It is found that silver, being strongly oxidized in dissociated carbon dioxide flow, can be considered as such reference material.

Effective recombination coefficients of O and CO on quartz are determined as functions of surface temperature. Detailed comparison of these coefficients with literature data for O-atoms

http://plasmalab.ipmnet.ru/GwLibrary/�


recombination on quartz is carried out. The recombination of O-atoms on quartz is confirmed to be the dominant process in dissociated CO2 flows.

1.4 Forms of integration within the work package and with other WPs

WP6.4 is directly connected with WP 5.4 and is a continuation of it. Results obtained in WP6.4 will be used in further activities in the framework of WP7.11 and can be considered as one of the main achievements of the SACOMAR Project.

1.5 Problem areas

Aerothermal heat transfer tests in dissociated CO2 flows can not provide directly sufficient data for development of multiparameter models based on both Eley-Rideal and Langmuir-Hinshelwood mechanisms, because measurement of the heat flux and surface temperature alone is in general not enough for determination of the model parameters, when their number is more than two.

2 Introduction

Since published Goulard’s paper [1] catalytic recombination rate KW became to be known as one classical aerothermodynamic parameter. For binary mixture of molecules and atoms in a rather simple way through boundary condition for the diffusion equation for atoms this effective coefficient represents quite complex and still ill-studied processes of atoms recombination on a body surface:

AWA cKJ The ratio of stagnation point heat flux to surfaces of different catalycity to the corresponding fully catalytic wall heat flux at different hypersonic velocities for the frozen two-species boundary layer is shown in Fig. 1.

Figure 1: Relative stagnation point heat flux vs catalytic recombination rate Kw [1]. 1 – metals, 2 – oxides, 3 – glass.

The problem of surface catalysis in aerothermochemistry at high surface temperature and low pressure becomes to be crucial during development of reusable thermal protection systems (TPS)


for the Space Shuttle orbiter [2,3] in US and Buran aerospace vehicle [4,5] in USSR. The reason is that catalytic heating, which is caused on the surface by atoms recombination, introduces uncertainty in laminar heating factor of 2-3 depending on trajectory parameters and surface area location [2-6].

Since middle of sixties up to now different technical approaches – thermal (macroscopic scale) and diffusion (microscopic scale) ones - have been used in order to predict surface catalycity of different materials with cold and hot surfaces in dissociated air, nitrogen and oxygen flows.

In thermal approaches different ground facilities - shock tunnels, arc-jet facilities, inductively heated plasma facilities, MESOX set-up - were used:

Shock tubes (M 1): determination of ’ [7,8];

Arc-jet facilities (M 1): determination of ’ [9-14];

RF-plasmatrons (M 1): determination of ’ [15-26];

MESOX set-up which associates a solar radiation concentrator and a microwave generator (mesoscopic scale): determination of catalytic scale of materials [27].

The flight experiments have been performed on the Space Shuttle and Buran vehicles in order to demonstrate catalycity heating effect and rebuild catalytic recombination rate Kw or ’ at the flight conditions (M 1) [28,29,4].

Diffusion approaches in general are divided on three ones:

Diffusion side arm reactors: determination of [8,30];

MESOX set-up (microscopic scale): determination of , [27];

Measurements of atom concentration in frozen boundary layer (actinometry, LIF): determination of [27,30].

Here we use definitions as follows: (01) is the catalytic recombination coefficient

surfacetheimpingingatomsofflux

surfaceatgrecombininatomsofflux

Effective recombination coefficient ’ = β, where 0 β 1 is an energy accommodation coefficient (catalytic efficiency). In the case β = 1 we have the correlation

A

WA

W

WW m

TRK

22

2

where catalytic efficiency of recombination 0 W 1.

Methodologies of the surface catalycity determination in the binary mixture of atoms and molecules are based on the stagnation point heat flux or concentration profiles measurements and indirect sophisticated techniques of the rebuilding a single parameter ’ or by using analytical solutions for the frozen boundary layer equations or CFD modeling of heat transfer and species diffusion in reacting boundary layer for appropriate test conditions.

At IPM an original approach has been developed for the study of catalytic heating effects in subsonic dissociated air, nitrogen and oxygen flows in order to predict the catalytic efficiencies of recombination of O and N atoms on metals, quartz, tile coating and antioxidation coating of carbon-


based materials [15-17,23,25]. It is described below in the section 5. This methodology is well accepted now in Europe [26].

At IPM appropriate aerothermal tests were carried out by 100-kW RF-plasmatron IPG-4. Inductively heated subsonic air flows meet requirements to duplicate flow physics in reacting boundary layer and real surface processes at the stagnation point, if the conditions of the local simulation are satisfied (total enthalpy, stagnation pressure and velocity gradient are the same as in flight, when a blunt nose radius of a vehicle is much larger than a radius of the test model) [15,31,32].

From engineering point of view acceptable agreement between ground test results in high enthalpy facilities and hypersonic flight data in terms of the efficient recombination coefficients for Space Shuttle and Buran vehicles were achieved [28,29]. For better understanding of the processes of N and O atoms recombination on TPS surface, different phenomenological and kinetic models of surface catalytic recombination at high temperatures have been developed [33-47].

All these models are based on assumption that the surface remains invariable and the Eley-Rideal and Langmuir-Hinshelwood mechanisms [33,34] control the surface reactions. Very recently a general finite-rate surface chemistry model has been developed, which allows representation of both catalycity and surface altering (e.g., oxidation, nitridation, sublimation reactions) [48,49].

3 Mars entry environment

When a space vehicle entries into the Mars atmosphere, heating of the surface occurs due to shock layer and wake radiation, laminar/turbulent transition and gas/surface interactions. Depending on flow conditions the last processes include ablation, oxidation and surface catalytic reactions. It should be noted that for capsules re-entering in the Earth atmosphere at the peak heating, surface catalysis does not play significant role in part of the trajectory, because shock layer environment is close to equilibrium due to high pressure behind the bow shock, and ablation is the dominant process. But the atmosphere of Mars is quite rarefied in comparison to Earth. Therefore, even for steep capsule trajectory surface catalytic reactions can contribute large portion in convective heating. In the case of relatively low entry speed convective heating becomes to be dominant in heat transfer in Mars atmosphere, and surface catalysis is the main source of uncertainties in heat flux rates not only in stagnation region, but along a vehicle surface [50-53]. Even on afterbody surface of Mars entry probe the role of surface catalysis in heat transfer at relatively low heat flux rates can be important [54].

In Fig. 2 the laminar convective heat flux along the Mars Pathfinder at baseline conditions at peak heating point is shown for both noncatalytic and fully catalytic wall [50]. The parameters at the entry trajectory point are as follows: = 2.810-4 kg/m3, V = 6.60 km/s, T = 169 K. The surface is supposed to be full catalytic with respect to reaction CO + O → CO2. Significant difference between the two curves is demonstrated along the forebody including stagnation point, midfrustum and shoulder.

EXOMARS entry conditions at the high enthalpy phase correspond to the flight velocity below 5230 m/s [55]. At this relatively low speed the chemical environment around a body can be represented by 5-species mixture of molecules and atoms: CO2, O2, CO, O and C. The two dominant surface reactions are O + O → O2 and CO + O → CO2, which are characterized by the two catalytic recombination rates KwO and KwCO, and corresponding contributions of above reactions in heat transfer is difficult to separate by both thermal and diffusion methods.


Figure 2: Laminar convective heat flux along the Mars Pathfinder at base line at peak heating point [50].

The coefficients KwO and KwCO can not be measured in heat transfer experiments. In order to determine catalytic properties of the material at low and high temperature, the indirect methodology based on measurements and computations of stagnation point heat fluxes in subsonic dissociated 5-species CO2 mixture assuming that wO = wCO = w has been developed at IPM [56-59]. In this report we present the standard IPM approach to determine the single effective parameter w - see sections 5, 7. This standard model will be applied to cold wall heat transfer tests with silver (high catalytic material), copper, stainless steel and quartz.

Below in chapter 12 we will suggest the improved models of O and CO recombination for EXOMARS entry conditions. These new models will be validated for high enthalpy tests in IPG-4 plasmatron later in WP7.11.

4 Gas/Surface reactions at cold wall test conditions

Gas/surface processes for real TPM materials at high surface temperatures still are rarely studied at severe entry conditions. The main surface processes can be listed as follows:

• Atom adsorption

• Atom and molecule desorption

• Atom migration (surface diffusion)

• Oxidation

• Surface degradation and aging

• Atom diffusion into material

• Ablation

• Atom-atom recombination according Eley-Rideal and Langmuir-Hinshelwood mechanisms (see Fig. 3).


Figure 3: Schematic of Eley-Rideal (a) and Langmuir-Hinshelwood (b) atom-atom recombination [61].

At low surface temperatures of metals and quartz, the processes of ablation, surface degradation and aging can be considered as negligible processes. The dominant ones become surface oxidation and catalysis. It is necessary to know that surface catalycity can depend on test conditions at the same surface temperature and pressure. The change of surface catalytic properties could occur due to the surface oxidation in the course of interaction with dissociated oxygen [60,61]. Our previous tests show that after some time of CO2 plasma action on silver surface, the latter becomes black (Fig. 4) and finally stable in terms of measured heat flux [62].

a b

Figure 4: Stationary water-cooled calorimeter with massive silver surface [62],

a – before experiment, b – after oxidizing in CO2 plasma flow.


For one of the tests in IPG-4 made for silver surface, it takes about 15 minutes to reach maximum heat flux, and then after saturation the value of stagnation heat flux remains constant (Fig. 5).

0 100 200 300 400 500 600 700 800 900

t, s

0

20

40

60

80

100

120

140

160

180

q, W

/cm

2

Figure 5: Time history of silver surface oxidation in CO2 plasma flow for the test regime Ptc = 76 hPa, Nap = 45 kW [62].

Therefore, when below we speak about catalycity of metals, we always mean strongly oxidized walls which are stable in terms of heat transfer.

5 IPM approach for predicting surface catalycity

The general philosophy of the IPM methodology for predicting surface catalycity consists in tight connection of the heat transfer tests with CFD simulation of stagnation point heat transfer in subsonic dissociated carbon dioxide flows. The logic of the surface catalycity determination is based on numerical extraction of the heat flux portion caused by heat of recombination of atoms for the test conditions. The methodology already has been applied for the study of the catalytic heating effects in subsonic dissociated air, nitrogen, oxygen and carbon dioxide [15-17,23,25,56-59].

In fact, the method is quite laborious, but it reveals a fair way for extrapolation of catalytic heating effects from ground tests to flight entry conditions, at least for stagnation point [32,58,59].

The IPM methodology of the TPM catalycity prediction includes the essential parts as follows:

1) production of the dissociated subsonic stable gas flows according test matrix;

2) experimental study of the steady-state heat transfer in stagnation point configuration;

3) demonstration of comparative catalycity heating effect and establishing catalycity scale for different cold wall materials;

4) search and application of the high catalytic material, which surface can be considered as reference fully catalytic one;


5) CFD modeling of reacting plasma and high enthalpy gas flows within plasma torch and around a test model;

6) rebuilding free stream conditions (enthalpy, velocity);

7) model of surface catalysis;

8) numerical computations of nonequilibrium multicomponent boundary layer flows modified for low Re test conditions taking into account the finite thickness of the boundary layer;

9) design of the heat flux envelopes for the subsonic test conditions;

10) uncertainties analysis;

11) extrapolation from ground test to atmospheric entry flight conditions.

The points (1) – (6) were considered in our previous SACOMAR report [62].

6 Demonstration of heating effect of surface recombination

Fig. 6 shows the results of stagnation point heat flux measurements for the three metals (silver, copper, stainless steel) and quartz as functions of the anode power Nap [62]. The tests were made in subsonic CO2 flow at testing chamber pressure 80 hPa. The heat flux probes were installed in 50-mm diameter (so called euromodel).

25 30 35 40 45 50 55

Nap, kW

0

50

100

150

200

250

q, W

/cm

2

Cu

Ag

quartzstainless steel

Figure 6: Stagnation point heat flux to different heat flux probes in subsonic CO2 flow at the pressure 80 hPa vs generator anode power [62].


The presented data for cold wall metals (300 K) and quartz can be arranged according catalytic scale as follows: Ag2OCu2OSteelSiO2. This scale is in good agreement with scaling [61] obtained on cold metals in pure dissociated oxygen: Ag2O Cu2O Fe2O3 ZnO Au.

7 IPM model of surface catalysis in CO2 mixture

The simple schemes of Eley-Rideal (a) and Langmuir-Hinshelwood (b) atom-atom recombination are shown above in Fig. 3. In our methodology the parameters which characterize surface catalycity have to be determined through comparison of the measured heat flux rates and surface temperatures with results of multiparameter computations (inverse problem). Therefore, the model of surface catalysis should contain consistent number of unknown parameters – actually the single parameter, or two parameters if it would be possible to separate contributions of different catalytic reactions in heat transfer with performing tests in different gases. But it is necessary to be careful, because the use of recombination coefficients obtained previously in pure oxygen or nitrogen flows could lead to inaccuracies [46,47].

Here we present the macrokinetic model of the catalytic recombination of O atoms and CO molecules formulated before in [56,57]:

• adsorption of the oxygen atoms dominants over other species adsorption;

• adsorption of O atoms and desorption of the products are fast reactions;

• recombination reactions follow Eley-Rideal mechanism: O + S → O_S;

O + O_S → O2 + S; CO + O_S → CO2 + S;

• recombination reaction C + 2O → CO2 follows the 2-step Langmuir-Hinshelwood mechanism: C + O_S → CO_S, CO_S + O_S → CO2 + 2S.

Here S is the surface site, O_S is adsorbed oxygen atom (adatom), CO_S is adsorbed CO molecule.

Simple schematic of Eley-Rideal mechanism looks as follows [39]:

Figure 7: Schematic of O-atom surface recombination according to Eley-Rideal mechanism [39].


8 Boundary conditions for diffusion equations of Goulard’s type

The above scheme leads to the first order reactions of O atoms, CO molecules and C atoms with three independent effective parameters – catalytic efficiencies wO, wCO and wC (0 wi 1). The case wO = wCO = wC = 0 corresponds to a noncatalytic wall, the case wO = wCO = wC = 1 – to a fully catalytic wall.

The effective probability w is introduced to describe in total the effect of catalytic reactions:

w = wO = wCO = wC. In this way we introduce the average efficiency of recombination w.

The reason for this simplification is that we have only one measured parameter qW to rebuild the surface catalycity.

So, reactions of surface recombination of O and C atoms and CO molecules are of the first order. Respectively, boundary conditions at the surface for mass concentrations of CO molecules, O and C atoms are the following:

COWCOCO cKJ

OWOO cKJ

CWCC cKJ

Here Ji is the diffusion mass flux for i-th species. Note that the catalytic recombination of C atoms gives a small input to the total heat flux for the test conditions [55] due to the small concentration of C atoms in boundary layer. So, the effective value w describes the effective surface recombination of O atoms and CO molecules.

In addition, it is necessary to use the single boundary condition of O atoms balance on the surface:

02

2

2

2 OCO

CO

OCO

CO

OO JJ

m

mJ

m

mJ

9 Previous IPM data for quartz and supporting literature results

As an example, calculated chart of stagnation point heat fluxes to the 50-mm diameter euromodel in comparison to the experimental points is shown in Fig. 8 for the subsonic pure oxygen flow at the pressure of 100 hPa and enthalpy of 19.6 MJ/kg corresponding to the generator anode power of Nap=45 kW [56].

The solid curves 1–7 show dependencies qw(Tw) at the constant wO= 1, 0.1, 3·10-2, 10-2, 3·10-3, 10-

3, and 0. The upper curve 1 corresponds to a fully catalytic wall, the lower curve 7 – to a noncatalytic surface. The low dash curve 8 is the dependency for the noncatalytic wall in the frozen boundary layer case. The deviation of the curve 7 from the curve 8 indicates the net contribution of gas-phase chemical reactions in heat transfer. When Tw increases the influence of gas-phase reactions in boundary layer on the heat transfer decreases and catalytic recombination of the atomic oxygen becomes the main nonequilibrium process, which influences the heat flux.


Figure 8: Heart flux envelope for pure oxygen flow at h=19.6 MJ/kg, p=100 hPa [56].

Calculated stagnation point heat flux chart for the euromodel in subsonic high-enthalpy carbon dioxide flow at the assumption wO = wCO = wC = w is shown in Fig. 9 for the test conditions p=100 hPa, h = 21.2 MJ/kg (Nap = 45 kW) [56]. The curves in Fig. 9 correspond to notations in Fig. 8. The data for the quartz in Fig. 8 are located along the curve 5 (wO ≈ 3·10-3), in Fig. 9 the quartz data are spaced along the curve 5 as well (w ≈ 3·10-3).

Figure 9: Heart flux envelope for CO2 flow at h=21.1 MJ/kg, p=100 hPa [56]. The notations in Fig. 9 are the same as in the Fig. 8.


From comparison of Figs. 8 and 9, we can see good agreement between the efficiency of the catalytic reaction O + O → O2 (wO) and the average efficiency (w) of the catalytic reactions O + O → O2 and CO + O → CO2 on the quartz surface points due to similarity of the heterogeneous recombination mechanisms in the carbon dioxide and pure oxygen dissociated gas flows.

Figure 10 from [57] presents the data for molybdenum at Tw = 300 K and for quartz in the surface temperature range Tw = 390-1470 K.

A molybdenum surface appears as a poor catalyst: w = 810-4.

In the temperature range Tw = 390-1470 K catalytic efficiency w of quartz increases monotonously if surface temperature increases. There is some scattering of the data obtained at weak and moderate heat transfer regimes, but the data obtained at strong high-enthalpy regimes showed Arrhenius-like behavior.

As we can see in Fig. 10 the data [57] on effective quartz catalycity in dissociated carbon dioxide flows are in good agreement with the well-known data on the recombination of the oxygen atoms on silica [63] and on reaction-cured glass applied in the Space Shuttle TPS [3]. This finding [57] is also consistent with experimental data [64] that O-atom recombination is the dominant reaction on quartz in mixtures of O and CO.

Figure 10: Comparison of data for average efficiency w

with the literature data for pure atomic oxygen recombination [57]. In Fig. 10 the average efficiency w describes in total the effect of catalytic reactions: w = wO = wCO = wC = w. Notations: Ref. 6 in Fig. 10 corresponds to [3], Ref. 33 – [63].

In [64] the relative importance of two possible reactions O + O O2 and CO + O CO2 on quartz has been investigated using a diffusion side-arm reactor together with two-photon laser-induced fluorescence for both O and CO species detection. The experiments showed: 1) the presence of CO in gas phase does not significantly affect the oxygen recombination reaction on quartz (Fig. 11); 2) the gas-phase CO concentration is not significantly altered by the presence of atomic oxygen (Fig. 12).


These results indicate that for the experimental conditions [64] the dominant surface reaction on quartz in oxygen-carbon mixtures is O + O O2. It is interesting the comment in [64] regarding the paper [57]: “The general finding of the study [57] was that catalytic heating contributions in dissociated carbon dioxide and dissociated oxygen were similar. This result is consistent with our finding that O-atom recombination is the dominant surface reaction on quartz in mixtures of O and CO."

Figure 11: Relative O-atom concentration along diffusion tube side arm, p=41.5 Pa [64].

Figure 12: Relative CO concentration along diffusion side arm at 295 K, p=49.6 – 50.7 Pa [64].


The recent work [65] is aimed at providing more information about surface catalyzed reactions for Mars exploration missions. Measurements of dissociated species above a copper catalytic surface are obtained using two-photon absorption laser-induced fluorescence (TALIF) implemented in a new 30 kW inductively coupled plasma torch facility.

In [65] we read: “Although the data are preliminary the trends suggest that O atom recombination does occur at the copper surface. The current trend in the relative densities determined from spectral fits obtained by LIF (over a limited spectral range) does not support CO participation in surface-catalyzed recombination reactions.” This conclusion supports our assumption that in dissociated CO2 flows the catalytic recombination of O-atoms plays the dominant role not only regarding quartz surface, but in heat transfer to high catalytic surfaces as well.

10 Role of standard high catalytic surface in predicting effective catalycity of materials

One of key points of IPM methodology for predicting surface catalycity is search of the material with high catalytic efficiency, which can be considered as the standard fully catalytic one. Such material should be selected through heat flux measurements with respect to maximum value of stagnation point heat flux rate. In dissociated air such property was demonstrated by the cold copper surface [15-17], in dissociated CO2 flows – the cold silver surface according previous [56-59] and very recent data [62]. One important finding [62] is that the silver surface properties were changing during long exposure in CO2 flows in accordance with altering heat flux rate (Fig. 5). Silver surface became black after oxidation in dissociated CO2 flow (Fig. 4).

Previously dynamic behaviour of catalysis on oxidized silver surface was observed in [60,61]. So, when we speak about standard silver surface catalytic properties, actually we have deal with strongly oxidized stable surfaces of monolith silver. Standing on this position, we consider the catalytic properties of other metallic surfaces – stable oxidized copper and stainless steel. In IPM approach the basic thing is that RF-plasmatron can operate continuously during long time period providing constant free stream conditions and constant heat flux to oxidized metallic surface. Quartz surface properties are exclusive ones – oxidation does not change them.

11 Determination of efficient recombination coefficients for metals and quartz at specified CO2 tests conditions using IPM approach

In the framework of the SACOMAR project, tests were carried out in dissociated CO2 flows of the IPG-4 facility for the pressure and enthalpy conditions close to the ones prescribed by the test matrix for IPM: P=80 and 40 hPa, he=13.8 and 9.0 MJ/kg. The details of the measurements techniques, enthalpy determination technique, and selection of the IPG-4 test regimes were presented in our previous report [62].

The tests were performed using extended discharge channel which consists of the usual quartz tube equipped with the special segmented water-cooled nozzle with exit diameter 40 mm and length 80 mm, in order to decrease flow enthalpy and to improve quality of subsonic flow at low generator power. The testing material samples were mounted in the standard euromodel with 50 mm diameter. IPG-4 test regimes are presented below in the Table 1 along with appropriate results of heat flux data qw, enthalpy values he determined for these regimes, and the temperature of the quartz sample external surface Tw (SiO2). The details of measurements and calculation techniques for these data were presented in our previous report [62].

The data presented in the Table 1 were used as input data in calculation of heat flux envelopes and surface catalycity of the tested materials. Calculation of the heat flux envelopes was made on the basis of numerical solution of the nonequilibrium boundary layer equations with account for finite layer thickness in framework of the standard IPM model of surface catalysis described previously in the chapters 7, 8 of this report. The equations and numerical solution technique were presented in our previous report [62].


Table 1: Test regimes and heat fluxes measured to the tested materials.

P

hPa

Nap

kW

Z mm

he

MJ/kg

qw(Ag)

W/cm2

qw(Cu)

W/cm2

qw(steel)

W/cm2

Tw(SiO2)

K

qw(SiO2)

W/cm2

80 40.4 40 14.0 142 116 93 755 70

80 34.0 40 8.8 93 75 66 599 45

40 35.0 72 14.4 125 85 72 606 46

40 35.0 122 9.5 78 59.5 45 500 30

Calculated heat flux envelopes for the four test regimes are presented in Figs. 13-16. The results of heat flux measurements for different tested materials are shown in the Figures by the symbols: triangle, rhomb, square are used for water-cooled calorimeters with the surface made of silver, copper, stainless steel, and the circle shows the heat flux to the quartz probe.

1

0.1

3.2e-2

1e-2

3.2e-31e-30

300 600 900 1200 1500 1800 21000

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

Tw, K

qw

W/cm2Frozen, =0

Ag

SiO2

Cu

Steel

Figure 13: Heat flux envelope and data for testing materials at the CO2 test regime: P=80 hPa, Nap=40.4 kW, Z=40 mm, he=14.0 MJ/kg.


1

0.1

3.2e-2

1e-2

3.2e-31e-30

300 600 900 1200 1500 1800 21000

10

20

30

40

50

60

70

80

90

100

Tw, K

qw

W/cm2 Frozen, =0

Ag

SiO2

Cu

Steel

Figure 14: Heat flux envelope and data for testing materials at the CO2 test regime: P=80 hPa, Nap=34 kW, Z=40 mm, he=8.8 MJ/kg.


1

0.1

3.2e-2

1e-2

3.2e-31e-30

300 600 900 1200 1500 1800 21000

10

20

30

40

50

60

70

80

90

100

110

120

130

Tw, K

qw

W/cm2Frozen, =0

Ag

SiO2

Cu

Steel



1

0.1

3.2e-2

1e-2

3.2e-31e-30

300 600 900 1200 1500 1800 21000

10

20

30

40

50

60

70

80

Tw, K

qw

W/cm2Frozen, =0

Ag

SiO2

Cu

Steel


The heat flux envelopes presented in Figs. 13-16 were calculated on the basis of the simple model of surface catalysis in dissociated CO2 mixture presented above in the sections 7 and 8, with use of the effective probability w introduced to describe in total the effect of catalytic reactions:

w = wO = wCO = wC. Values of w are shown in Fig. 13-16 to the right of the appropriate curves.

Values of w calculated for the tested materials by the measured heat fluxes qw(Cu), qw(steel), qw(SiO2) are presented in the Table 2 for the four test regimes.


Table 2: Effective probability w determined for the tested materials (copper, stainless steel, quartz) for the four test regimes.

P

hPa

Nap

kW

Z

mm

he

MJ/kg

w(Cu) w(steel) Tw(SiO2)

K

w(SiO2)

80 40.4 40 14.0 2.21e-2 8.48e-3 755 7.84e-3

80 34.0 40 8.8 1.93e-2 1.07e-2 599 4.97e-3

40 35.0 72 14.4 1.87e-2 1.13e-2 606 5.71e-3

40 35.0 122 9.5 2.39e-2 8.77e-3 500 3.42e-3

The obtained values of w for copper and stainless steel vary within 30% with changes of pressure and enthalpy.

The values of w for quartz (shown by red and neon-red circles in the Fig. 17) vary more than factor two with the change of quartz surface temperature. They lay close to the straight line in semi-logarithmic scale as function of 1000/Tw, that is close to Arrhenius function. The influence of pressure on w for quartz is small in these tests.

Below the Fig. 17 shows the comparison of the obtained w data for quartz surface with appropriate data obtained earlier in IPG-4 tests in dissociated CO2 flows (2000 and 1998 years) and in dissociated pure oxygen flow (1998). Also, Fig. 17 shows some literature data of different authors on WO for oxygen atoms recombination on quartz surface obtained in pure oxygen flows and in air + 5% argon flows.

Notations used in Fig. 17 are presented in the next Fig. 18.


w

0.5 1 1.5 2 2.5 3 3.51E-004

1E-003

1E-002

1000/Tw, K

IPMechSACOMAR2011

GreavesLinnett1959

Dickens 1964

Berkowitz1969

Kim1991

Marschall 1997

Krongelb 1959

Marshall 1962

Balat 2007

IPMech1998-2001

Figure 17: Data on w for quartz surface obtained in CO2 and pure oxygen flows.


P=80 hPa P=40 hPa

Nap=29 kW Nap=52 kW

Nap=64 kW

CO2, SACOMAR, 2011

CO2, P=100 hPa, Kolesnikov, J. Spacecraft & Rockets, 2000 [57]

Nap=72 kW

CO2, P=0.1 atm, Kolesnikov, ESA-SP-426, Noordwijk, 1998 [56]

Data on w and O for quartz surface obtained in CO2 and pure oxygen tests

Nap=45 kW Nap=52 kW

Nap=64 kW

Pure oxygen, P=0.1 atm, Kolesnikov, ESA-SP-426, Noordwijk, 1998 [56]

Nap=45 kW Nap=52 kW

Nap=64 kW

1. Data on w obtained in IPG-4 tests, IPMech

2. Literature data on O for quartz surface

Greaves & Linnett. Tr. Faraday Soc. 1959 [63,73]. Averaged data

Dickens and Sutcliffe. Trans. Faraday Soc. 1964 [71]

Marshall. Phys. Fluids, 1962 [80]

Krongelb and Stranberg. J. Chem. Phys. 1959 [78]

Marschall. AIAA Paper 97-3879, 1997 [30]

Berkowitz. In: Structure and chemistry of solid surface. Wiley, 1969 [69]

Kim and Boudart. Langmuir, 1991 [76]

Balat-Pichelin. RTO-EN-AVT-142, 2007 [66] ( = O*

Greaves & Linnett. Tr. Faraday Soc. 1959 [63]. Original data

Figure 18: Notations used in Fig. 17.


12 Two models of surface catalysis adapted to the EXOMARS entry conditions

12.1 Two-parameter model based on Eley-Rideal mechanism

Mass concentration of C atoms in boundary layer in the case of the EXOMARS trajectory is very small due to relatively low enthalpy. Therefore assumptions of paragraph 7 can be simplified assuming that diffusion flux of C atoms to the wall is negligible. IPM single-parameter model for the 1-st order surface catalytic reactions is modified according the general model [38] based on the theory of Langmuir ideal adsorbing layer for Eley-Rideal mechanism, which dominates on cold walls. Finally, we have boundary conditions for diffusion equations on surface with the two recombination rates KWO and KWCO as follows:

COWCOCO

OOWOO cK

m

mcKJ (1)

COWCOCO cKJ (2)

0CJ (3)

and

02

2

2

2 OCO

CO

OCO

CO

OO JJ

m

mJ

m

mJ (4)

In this new two-parameter model, when the catalytic recombination rate KwO depends only on surface temperature, it can be taken from the data for pure atomic oxygen recombination and in that case the second recombination rate KwCO can be rebuilt from heat flux measurements in CO2 plasma flows. In fact, for KwO or wO we can use the data from literature, if they are available at the same surface temperature, for example from [39,63].

In the above two-parameter simple model (1)-(3) the catalytic recombination rates depend on surface temperature according the Eley-Rideal mechanism and have the structure as follows:

COOim

TRK

TR

EkTRK

i

WA

Wi

WiWi

WA

ERiER

iWAWi ,,22

2,exp2

(5)

12.2 Single-parameter model based on Langmuir-Hinshelwood mechanism - atoms diffusion on high temperature surface

It is necessary to know that at high surface temperature Langmuir-Hinshelwood mechanism (diffusion of atoms on surface) becomes more important in comparison with Eley-Rideal mechanism. If the process of O-atoms surface diffusion and recombination is dominant, recombination of CO molecules does not occur and the two-step scheme of the surface reactions is as follows:

• O + S →O_S;

• O_S + O_S → O2 + 2S

Correspondingly, the boundary conditions for the species mass diffusion equations will have rather simple form:

0;0;0;2

CCOCOOWOO JJJcKJ (6)


In above equations (6) the structure of the catalytic recombination rate KwO looks different in comparison with Eley-Rideal mechanism:

WA

LHWA

O

LHO

WO TR

ETR

px

kK exp

2 (7)

It is obvious that in this case we cannot use the recombination rate KWO obtained in pure oxygen experiment. The combination (KWOpxO) depends only on surface temperature and it is more conservative. The catalytic efficiency W depends on TW even slightly. The last new single-parameter model (6)-(7) looks easier for the experimental validation than previous two-parameter one (1)-(5).

13 Electronic library with published experimental data on surface catalytic properties for different materials - GwLibrary

Electronic library GwLibrary presents published experimental data on surface catalytic properties for different testing materials - metals (silver, copper, and some other metals), quartz (SiO2), SiO2-based coatings, sintered SiC, etc.

GwLibrary presents the data on surface recombination of oxygen atoms O obtained either in dissociated pure oxygen, CO2 and CO2+argon flows, or in dissociated air and air+argon flows. Also, GwLibrary presents the effective surface recombination coefficient (w) for O and C atoms and CO molecules obtained in dissociated CO2 flows.

GwLibrary in fact is the electronic database, the appropriate DBMS (database management system) was developed to provide the access to GwLibrary via Internet Web-site. It is available at http://plasmalab.ipmnet.ru/GwLibrary/

The shortened version of GwLibrary is presented as a table in this report.

The following data are presented in GwLibrary:

Gw (or ) - recombination coefficient determined for the single species, energy accommodation is not included;

Beta (or β) - chemical energy accommodation coefficient for the single species;

Gweff (or ’ = β) - effective recombination coefficient, including energy accommodation effect, for the single species, or for the group of species (e.g. Gweff = w = wO = wCO = wC for tests in dissociated CO2 flow).

These data are presented with reference to the authors (including the article or report, institution and experimental setup, when available), the testing material, and the appropriate experimental conditions, available from the publication.

Additional data on the material surface constitution (type of surface oxide), details of the experiment, etc. are presented, when available.

GwLibrary includes the experimental data obtained both in IPM Plasma Laboratory (IPG-4 setup) and in other institutions in different countries (Russia, Western Europe, USA, and others).

At present, GwLibrary contains 169 lines, each line provides the information on surface catalytic properties for one of the materials, obtained from one reference. In total, 30 references (papers, proceedings, reports, sections of books, etc.) were used to collect data for GwLibrary.

New data will be supplemented in GwLibrary over time.



The structure of GwLibrary

GwLibrary consists of the following 14 columns:

1. Working gas

2. Species contributing to Gw (and/or Gweff, Beta)

3. Testing material

4. Gweff - effective recombination coefficient, including energy accommodation effect, for the single species, or group of species

5. Gw - recombination coefficient determined for the single species, energy accommodation is not included

6. Beta - chemical energy accommodation coefficient for the single species

7. Pressure P, hPa

8. Surface temperature Tw, K

9. Enthalpy h, MJ/kg

10. Reference

11. Institution

12. Experimental setup

13. Comments

14. Extended comments (this column is reserved but is not used yet in 1st version)

Normally, each line provides some data in a part of fields and has gaps in other fields due to lack of information available in a reference. These gaps are marked by "n/a" or are left empty.

Below the shortened version of GwLibrary is presented as a table continued in several pages. The field "Reference" here contains only the name of the first author and the appropriate reference number.

Table 3: Published experimental data on surface catalytic properties for different materials from GwLibrary.

Working gas Species Material Gweff Gw Beta P Tw h Reference Comment

O2 O Ag n/a 2,4e-1 n/a 6 300 n/a Greaves [73]

O2 O Ag 2,3e-1 2,4e-1 0,95 100 300 n/a Melin [82]

O2 O Ag n/a 2,2e-1 n/a 1 300 n/a May [81]

O2 O Ag 1,4e-2 1,5e-2 0,91 3 313 n/a Cauquot [61]

Ar+10%O2 O Ag n/a 1,2e-1 n/a 8 300 n/a Myerson [83]

Ar+10%O2 O Ag n/a 5,0e-2 n/a 1e-5 300 n/a Loomis [79]

Air O Ag n/a 1,3e-1 n/a n/a 300 n/a Starner [86]

Air O Ag n/a 1,4e-2 n/a 10 350 n/a Pope [84]

O2 O Cu n/a 1,1e-1 n/a 133 300 n/a Dickens [71] Cu2O

O2 O Cu n/a 2,7e-1 n/a 133 500 n/a Dickens [71] Cu2O

O2 O Cu n/a 4,5e-2 n/a 133 300 n/a Dickens [71] CuO



O2 O Cu n/a 7,5e-2 n/a 133 450 n/a Dickens [71] CuO

O2 O Cu n/a 1,7e-1 n/a 0,06 300 n/a Greaves [72]

O2 O Cu n/a 2,0e-2 n/a 0,06 300 n/a Greaves [72] Oxidized surface

O2 O Cu n/a 4,3e-2 n/a 0,06 300 n/a Greaves [73]

O2 O Cu n/a 1,5e-1 n/a 0,4 300 n/a Prock [85]

O2 O Cu 4,5e-3 1,5e-2 0,3 100 300 n/a Melin [82]

Ar+10%O2 O Cu n/a 3,1e-2 n/a 8 300 n/a Myerson [83]

CO2 O,CO,C Cu 1,6e-2 n/a n/a 100 300 14,4 Kolesnikov [57]








Air O Cu n/a 2,0e-2 n/a 10 350 n/a Pope [84]

Air O Cu 2,1e-2 n/a n/a n/a 300 n/a Anderson [10]

O2 O Steel 2,6e-3 7,1e-3 0,36 3 313 n/a Cauquot [61]

CO2 O Steel 8,5e-3 n/a n/a 80 300 14,0 Kolesnikov [88]




O2 O Au n/a 5,2e-2 n/a 0,06 300 n/a Greaves [72]

O2 O Au 2,2e-3 5,0e-3 0,45 3 313 n/a Cauquot [61]

Ar+10%O2 O Au n/a 5,0e-3 n/a 8 300 n/a Myerson [83]

O2 O Zn 2,4e-3 4,3e-3 0,55 3 313 n/a Cauquot [61]

CO2 O,CO,C Mo 1,3e-3 n/a n/a 100 300 14,4 Kolesnikov [57]






O2 O SiO2 n/a 1,6e-4 n/a 0,06 300 n/a Greaves [73]

O2 O SiO2 n/a 1,8e-4 n/a 0,16 293 n/a Greaves [63] Averaged data

O2 O SiO2 n/a 1,4e-2 n/a 0,16 873 n/a Greaves [63] Averaged data

O2 O SiO2 n/a 2,2e-4 n/a 0,16 292,1 n/a Greaves [63]

O2 O SiO2 n/a 1,6e-4 n/a 0,16 292,5 n/a Greaves [63]










O2 O SiO2 n/a 3,5e-4 n/a 133 300 n/a Dickens [71]

O2 O SiO2 n/a 5,0e-3 n/a 133 600 n/a Dickens [71]

O2 O SiO2 n/a 4,0e-5 n/a n/a 300 n/a Hacker [75]

O2 O SiO2 n/a 2,0e-4 n/a 5 770 n/a Berkowitz [69]

O2 O SiO2 n/a 5,0e-4 n/a 5 1110 n/a Berkowitz [69]

O2 O SiO2 n/a 2,0e-4 n/a 0,27 920 n/a Kim [76]





O2 O SiO2 n/a 2,5e-4 n/a 0,4 500 n/a Marschall [30]

O2 O SiO2 n/a 3,2e-4 n/a n/a 300 n/a Krongelb [78]

O2 O SiO2 n/a 5,0e-4 n/a 3 300 n/a Marshall [80]

O2 O SiO2 n/a 1,0e-3 n/a 133 300 Berkut [70]

O2 O SiO2 4,1e-3 n/a n/a 101 556 19,6 Kolesnikov [56]











CO2 O,CO,C SiO2 4,9e-4 n/a n/a 100 390,7 14,4 Kolesnikov [57]

CO2 O,CO,C SiO2 1,9e-4 n/a n/a 100 499,4 14,4 Kolesnikov [57]

CO2 O,CO,C SiO2 2,5e-4 n/a n/a 100 601 14,4 Kolesnikov [57]




























Air+5%Argon O SiO2 n/a 4,9e-3 n/a 2 850 n/a Bedra [68] quartz

Air+5%Argon O SiO2 n/a 8,0e-3 n/a 2 1000 n/a Balat-Pichelin [67] quartz



Air+5%Argon O SiO2 2,0e-2 2,7e-2 0,732 2 1000 n/a Balat-Pichelin [66] cristobalite




Air+5%Argon O SiO2 n/a 9,4e-3 n/a 2 800 n/a Bedra [68] cristobalite

Air+5%Argon O SiO2 n/a 2,7e-2 n/a 2 1000 n/a Balat-Pichelin [67] cristobalite





CO2 O,CO,C SiO2 8,1e-3 n/a n/a 37 1453 16,4 Kolesnikov [77] tile-coating



CO2 O,CO,C SiO2 4,0e-3 n/a n/a 100 1600 17 Kolesnikov [59] tile-coating


Air O RCG-tile n/a 1,5e-2 n/a n/a 1449 7,3 Willey [87]










N2+11%O2 O RCG-tile n/a 1,2e-2 n/a n/a 1456 6,5 Willey [87]

N2+11%O2 O RCG-tile n/a 2,0e-2 n/a n/a 1479 7 Willey [87]




Air O RCG-tile n/a 1,8e-2 n/a 2 1450 n/a Kolodziej [12]








Air O RCG-tile n/a 1,7e-4 n/a n/a 800 n/a Gupta [74]




CO2 O,CO,C SiC 6,6e-3 n/a n/a 37 1426 16,4 Kolesnikov [77] sintered SiC

CO2 O,CO,C SiC 4,9e-3 n/a n/a 96 1536 16,2 Kolesnikov [77] sintered SiC

Air+5%Argon O Al2O3 n/a 2,9e-2 n/a 3 1000 n/a Balat-Pichelin [67] type-A





Air+5%Argon O Al2O3 n/a 5,1e-2 n/a 3 1000 n/a Balat-Pichelin [67] type-B





Air+5%Argon O Al2O3 n/a 1,2e-2 n/a 3 1000 n/a Balat-Pichelin [67] type-C





14 Conclusions

Review of literature related to the methods of determination of catalytic recombination rates and appropriate data are presented.


Effective recombination coefficients of O-atoms and CO-molecules (w) on water-cooled copper, stainless steel and quartz probe in the four selected subsonic high-enthalpy carbon dioxide flow regimes are determined using IPM standard methodology.

Novel two-parameter model of O-atoms and CO-molecules surface recombination based on Eley-Rideal mechanism is proposed.

Model of O-atoms surface recombination based on Langmuir-Hinshelwood mechanism (atoms diffusion) is discussed.

Published experimental data on surface catalytic properties for different testing materials - metals (silver, copper), quartz, SiO2-based coatings, and some other materials - obtained in the flows that contain O atoms (pure oxygen, CO2, air) are analyzed and collected in the electronic library (GwLibrary). At present, GwLibrary contains 169 lines, each line provides the information on surface catalytic properties for one of materials, obtained from one reference. In total, 30 references (papers, proceedings, reports, sections of books) were used to collect the data.

GwLibrary presents the following surface catalytic properties:

Gw (or ) - recombination coefficient for single species;

Beta (or β) - chemical energy accommodation coefficient for single species;

Gweff (or ’ = β) - effective recombination coefficient, including energy accommodation effect, for single species;

Gweff (or w) - effective recombination coefficient, including energy accommodation effect, for group of species.

GwLibrary in fact is the electronic database, the appropriate DBMS (database management system) was developed to provide the access to GwLibrary via Internet Web-site.

It is available at http://plasmalab.ipmnet.ru/GwLibrary/

The shortened version of GwLibrary is presented as a Table 3 in this report.

15 References

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[2] Tong, H., Morse, H.L., Curry, D.M.: Application of Nonequilibrium Viscous-layer Computational Procedure to Evaluation of Space Shuttle TPS requirements and material performance. J. Spacecraft and Rockets. Vol. 12, No. 12, 1975, pp. 739-743

[3] Stewart, D.A., Henline, W.D., Kolodziej, P., Pincha, M.W.: Effect of Surface Catalysis in Heating to Ceramic Coated Thermal Protection Systems for Transatmospheric Vehicles. AIAA Paper 88-2706, June 1988

[4] Zalogin, G.N., Lunev, V.V.: Catalytic Properties of Materials in a Nonequilibrium Dissociated Air Flow. Fluid Dynamics, Vol. 32, No. 5, 1997, p. 748

[5] Voinov, L.P.: Thermal Designing of the BURAN Orbital Spaceship. In: Aerospace Systems, Ed. By G.E. Lozino-Lozinsky and A.G. Bratukhin. Moscow: Publishing House of Moscow Aviation Institute, 1997, 416 pp. (in Russian)

[6] Vlasov, V.I., Zalogin, G.N., Lunev, V.V.: Material Catalycity Effect on the Heat Transfer to Hypersonic Flight Vehicles in Multicomponent Gas Mixtures. In: European Conf. on Aerospace Sci. (EUCASS), Moscow, 2005

[7] Vidal, R.J., Golian, T.C.: Heat Transfer Measurements with a Catalytic Flat Plate in Dissociated Oxygen. AIAA J., Vol. 5, No. 9, 1967, pp. 1579-1588



[8] Berkut, V.D., Doroschenko, V.M., Kovtun, V.V., Kudrjavtzev, N.N.: Nonequilibrium Physico-Chemical Processes in Hypersonic Aerodynamics. Moscow: Energoatomizdat, 1994 (in Russian)

[9] Rosner, D.E.: Analysis of Arc-Tunnel Heat Transfer Data. AIAA J. Vol. 2, No. 5, 1964, pp. 945-948

[10] Anderson, L.A.: Effect of Surface Catalytic Activity on Stagnation-Point Heat Transfer Rates. AIAA J. Vol. 11, No. 5, 1973, pp. 649-656

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[12] Kolodziej, P., Stewart, D.A.: Nitrogen Recombination on High-Temperature Reusable Surface Insulation and the Analysis of its Effect on Surface Catalysis. AIAA paper 87-1637, 1987

[13] Stewart, D.A.: Determination of Surface Catalytic Efficiency for Thermal Protection Materials – Room Temperature to their Upper Use Limit. AIAA paper 96-1863, June 1996

[14] Stewart, D.A., Chen, Y.-K., Bamford, D.G., Romanovsky, A.B.: Predicting Material Surface Catalytic Efficiency Using Arc-Jet Tests, AIAA Paper 1995-2013, June 1995

[15] Kolesnikov, A.F.: The Aerothermodynamic Simulation in Sub- and Supersonic High Enthalpy Jets: Experiment and Theory. Ed. By J.J. Hunt. Proceedings of the Second European Symposium on Aerothermodynamics for Space Vehicles, ESA SP-367, February 1995, pp. 583-590

[16] Vasil’evskii, S.A., Kolesnikov, A.F., Yakushin, M.I.: Mathematical Models for Plasma and Gas Flows in Induction Plasmatrons. Ed. by M. Capitelli, Molecular Physics and Hypersonic Flows, NATO ASI Series, Vol. 482, Kluwer, 1996, pp. 495-504

[17] Kolesnikov, A.F.: Combined Measurements and Computations of High Enthalpy and Plasma Flows for Determination of TPM Surface Catalycity. RTO AVT/VKI Special Course on Measurement Techniques for High Enthalpy Plasma Flows, RTO EN-1, VKI, October 1999, pp. 8A-1 - 8A-16

[18] Conte, D., Sauvage, N., Tran, P., Vervisch, P., Bourdon, A., Desportes, A.: EADS-LV and CORIA Common Approach on Catalycity Measurement. 4th European Workshop on Hot Structures and Thermal Protection Systems for Space Vehicles, 2002

[19] Vlasov, V.I., Zalogin, G.N., Zemlyanskii, B.A., Knot’ko, V.B.: Methods and Results of an Experimental Determination of the Catalytic Activity of Materials at High Temperatures. Fluid Dynamics, Vol. 38, No. 5, 2003, pp. 815-825

[20] Pidan, S., Auweter-Kurtz, M., Fertig, M., Herdrich, G., Laux, T., Trabant, U.: Catalytic Behavior of Candidate Thermal Protection Materials. Proceedings of 5th European Symposium on Aerothermodynamics for Space Vehicles. ESA SP-563, February 2005, pp. 95-104

[21] Pidan, S., Auweter-Kurtz, M., Herdrich, G., Fertig, M.: Recombination Coefficients and Spectral Emissivity of Silicon-Carbide-Based Thermal Protection Materials. J. Thermophysics and Heat Transfer, Vol. 19, No. 4, 2005, pp. 566-571

[22] Schussler, M., Auweter-Kurtz, M., Herdrich, G., Lein, S.: Surface Characterization of Metallic and Ceramic TPS-Materials for Reusable Space Vehicles, Acta Astronautica, Vol. 65, No. 5-6, 2006, pp. 676-686


[23] Kolesnikov, A.F., Gordeev, A.N., Vasilevsky, S.A.: Simulation of Stagnation Point Heating and Predicting Surface Catalycity for the EXPERT Re-Entry Conditions. The 6th European Symposium on Aerothermodynamics for Space Vehicles, ESA SP-659, Versailles, France, November 2008

[24] Chazot, O., Krassilchikoff, H.W., Thoemel, J.: TPS Ground Testing in Plasma Wind Tunnel for Catalytic Properties Determination. AIAA paper 2008-1252, January 2008

[25] Kolesnikov, A.F., Gordeev, A.N., Vasilevskii, S.A.: Capabilities of RF-Plasmatron IPG-4 for Re-Entry Simulation. J. of Technical Physics, Vol. 50, No. 3, 2009, pp. 181-198 (Polish Academy of Sciences, Institute of Fundamental Technological Research, Warszawa)

[26] Chazot, O., Panerai, F., Muylaert, J.-M., Thoemel, J.: Catalysis Phenomena Determination in Plasmatron Facility for Flight Experiment Design. AIAA paper 2010-1248, January 2010

[27] Balat-Pichelin, M.: Applications: Experimental Investigation of Surface Reactions. In: Physico-Chemical Models for High-Enthalpy and Plasma Flows. Lecture Series 2002-07. VKI, 2002

[28] Rakich, J.V., Stewart, D.A.: Results of Flight Experiment on the Catalytic Efficiency of the Space Shuttle Heat Shield. AIAA paper 82-0944, June 1982

[29] Voinov, L.P., Zalogin, G.N., Lunev, V.V., Timoshenko, V.P.: Comparative Analysis of the Laboratory and Full-Scale data on the catalycity of the Heat Shields of the Bor and Buran Flight vehicles. Kosmonavtica i Raketostroenie, No. 2, p. 51, 1994 (in Russian)

[30] Marschall, J.: Experimental Determination of Oxygen and Nitrogen Recombination Coefficients at Elevated Temperatures Using Laser-Induces Fluorescence. 1997 National Heat Transfer Conference, Baltimore, MD, 1997 (AIAA Paper 97-3879)

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