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Extinction Simulation of a Diffusion FlameEstablished in Microgravity
presented by Guillaume Legros(1)
in collaboration withA. Fuentes(1), B. Rollin(1), P. Joulain(1),
J.P. Vantelon(1), and J.L. Torero(2)
(1) Laboratoire de Combustion et de Détonique (UPR 9028 du CNRS) – Poitiers (France)(2) School of Engineering and Electronics, The University of Edinburgh – Edinburgh (United
Kingdom)
4th International Conference on Computational Heat and Mass Transfer Cachan, May, 19th, 2005
Plausible Spacecraft Fire Scenario:
INTRODUCTION
INTRODUCTION
EXPERIMENT
SIMULATION
COMPARISON
CONCLUSIONS
condensed fuel
oxidizer blowingvelocity: Vox
Plausible Spacecraft Fire Scenario:
INTRODUCTION
condensed fuel
oxidizer blowingvelocity: Vox
extinction !
INTRODUCTION
EXPERIMENT
SIMULATION
COMPARISON
CONCLUSIONS
Investigating extinction:
O2 level
oxidizer balance gaz
VOX
condensed fuel nature
INTRODUCTION
need of valuable numerical simulations
INTRODUCTION
EXPERIMENT
SIMULATION
COMPARISON
CONCLUSIONS
Investigating extinction:
O2 level
oxidizer balance gaz
VOX
condensed fuel nature
INTRODUCTION
need of valuable numerical simulations
INTRODUCTION
EXPERIMENT
SIMULATION
COMPARISON
CONCLUSIONS
Investigating extinction:
O2 level
oxidizer balance gaz
VOX
condensed fuel nature
INTRODUCTION
need of valuable numerical simulations
INTRODUCTION
EXPERIMENT
SIMULATION
COMPARISON
CONCLUSIONS
Investigating extinction:
O2 level
oxidizer balance gaz
VOX
condensed fuel nature
INTRODUCTION
need of valuable numerical simulations
INTRODUCTION
EXPERIMENT
SIMULATION
COMPARISON
CONCLUSIONS
Investigating extinction:
O2 level
oxidizer balance gaz
VOX
condensed fuel nature
INTRODUCTION
need of valuable numerical simulationsfor steady-state phenomena
INTRODUCTION
EXPERIMENT
SIMULATION
COMPARISON
CONCLUSIONS
Experimental Environment:
Parabolic flights
microgravity duration = 22 s
a parabola every 2 minutes
EXPERIMENTAL PROCEDURE
easy ignition
+ fast transition to steady-state
INTRODUCTION
EXPERIMENTEnvironmentMeasurement
SIMULATION
COMPARISON
CONCLUSIONS
EXPERIMENTAL PROCEDURE
easy ignition
+ fast transition to steady-state
INTRODUCTION
EXPERIMENTEnvironmentMeasurement
SIMULATION
COMPARISON
CONCLUSIONS
Experimental Environment:
Parabolic flights
microgravity duration = 22 s
a parabola every 2 minutes
EXPERIMENTAL PROCEDURE
easy ignition
+ fast transition to steady-state
INTRODUCTION
EXPERIMENTEnvironmentMeasurement
SIMULATION
COMPARISON
CONCLUSIONS
Experimental Environment:
Parabolic flights
microgravity duration = 22 s
a parabola every 2 minutes
EXPERIMENTAL PROCEDURE
easy ignition
+ fast transition to steady-state
INTRODUCTION
EXPERIMENTEnvironmentMeasurement
SIMULATION
COMPARISON
CONCLUSIONS
Experimental Environment:
Parabolic flights
microgravity duration = 22 s
a parabola every 2 minutes
EXPERIMENTAL PROCEDURE
easy ignition
+ fast transition to steady-state
INTRODUCTION
EXPERIMENTEnvironmentMeasurement
SIMULATION
COMPARISON
CONCLUSIONS
Experimental Environment:
EXPERIMENTAL PROCEDURE
easy ignition
+ fast transition to steady-state
oxidizer blowingvelocity: Vox
ethylene injectionvelocity: VF
1 cm
INTRODUCTION
EXPERIMENTEnvironmentMeasurement
SIMULATION
COMPARISON
CONCLUSIONS
Experimental Measurement:
EXPERIMENTAL PROCEDURE
INTRODUCTION
EXPERIMENTEnvironmentMeasurement
SIMULATION
COMPARISON
CONCLUSIONS
Experimental Measurement:
CH* chemiluminescence
Iflame(λ=431 nm) α ICH* [1]
[1] Berg et al. (2000)
EXPERIMENTAL PROCEDURE
INTRODUCTION
EXPERIMENTEnvironmentMeasurement
SIMULATION
COMPARISON
CONCLUSIONS
Experimental Measurement:
CH* chemiluminescence
ICH* α volumetric combustion rate [2]
[2] McManus et al. (1995)
EXPERIMENTAL PROCEDURE
INTRODUCTION
EXPERIMENTEnvironmentMeasurement
SIMULATION
COMPARISON
CONCLUSIONS
Experimental Measurement:Map by CH* chemiluminescence
EXPERIMENTAL PROCEDURE
oxidizer blowingvelocity: Vox
ethylene injectionvelocity: VF
1 cm
INTRODUCTION
EXPERIMENTEnvironmentMeasurement
SIMULATION
COMPARISON
CONCLUSIONS
Experimental Measurement:Map by CH* chemiluminescence
EXPERIMENTAL PROCEDURE
oxidizer blowingvelocity: Vox
1 cm
α map of volumetric combustion rate
INTRODUCTION
EXPERIMENTEnvironmentMeasurement
SIMULATION
COMPARISON
CONCLUSIONS
Validating numerical extinction:
O2 level = 35%
oxidizer balance gaz = N2
fuel = C2H4
Vox = parameter
comparison based on volumetric combustion rate
NUMERICAL PROCEDURE
INTRODUCTION
EXPERIMENT
SIMULATIONGoalToolDomain
COMPARISON
CONCLUSIONS
Validating numerical extinction:
O2 level = 35%
oxidizer balance gaz = N2
fuel = C2H4
Vox = parameter
comparison based on volumetric combustion rate
NUMERICAL PROCEDURE
INTRODUCTION
EXPERIMENT
SIMULATIONGoalToolDomain
COMPARISON
CONCLUSIONS
Validating numerical extinction:
O2 level = 35%
oxidizer balance gaz = N2
fuel = C2H4
Vox = parameter
comparison based on volumetric combustion rate
NUMERICAL PROCEDURE
INTRODUCTION
EXPERIMENT
SIMULATIONGoalToolDomain
COMPARISON
CONCLUSIONS
Validating numerical extinction:
O2 level = 35%
oxidizer balance gaz = N2
fuel = C2H4
Vox = parameter
comparison based on volumetric combustion rate
NUMERICAL PROCEDURE
INTRODUCTION
EXPERIMENT
SIMULATIONGoalToolDomain
COMPARISON
CONCLUSIONS
Validating numerical extinction:
O2 level = 35%
oxidizer balance gaz = N2
fuel = C2H4
Vox = parameter
comparison based on the mapof volumetric combustion rate
NUMERICAL PROCEDURE
INTRODUCTION
EXPERIMENT
SIMULATIONGoalToolDomain
COMPARISON
CONCLUSIONS
Numerical Tool:Variant of Fire Dynamics Simulator (FDS):
transient 3D Navier-Stokes equations (low Mach number approximation)
allowing large density and temperature changes Direct Numerical Simulation mixture fraction / finite kinetics – no soot model Radiative Transfer Equation (non-scattering approximation)
RTE
Finite Volume Method Wideband model ( H2O + CO2 )
NUMERICAL PROCEDURE
INTRODUCTION
EXPERIMENT
SIMULATIONGoalToolDomain
COMPARISON
CONCLUSIONS
Numerical Tool:Variant of Fire Dynamics Simulator (FDS):
transient 3D Navier-Stokes equations (low Mach number approximation)
allowing large density and temperature changes Direct Numerical Simulation mixture fraction / finite kinetics – no soot model Radiative Transfer Equation (non-scattering approximation)
RTE
Finite Volume Method Wideband model ( H2O + CO2 )
NUMERICAL PROCEDURE
INTRODUCTION
EXPERIMENT
SIMULATIONGoalToolDomain
COMPARISON
CONCLUSIONS
Numerical Tool:Variant of Fire Dynamics Simulator (FDS):
transient 3D Navier-Stokes equations (low Mach number approximation)
allowing large density and temperature changes Direct Numerical Simulation mixture fraction / finite kinetics – no soot model Radiative Transfer Equation (non-scattering approximation)
RTE
Finite Volume Method Wideband model ( H2O + CO2 )
NUMERICAL PROCEDURE
INTRODUCTION
EXPERIMENT
SIMULATIONGoalToolDomain
COMPARISON
CONCLUSIONS
Numerical Tool:Variant of Fire Dynamics Simulator (FDS):
transient 3D Navier-Stokes equations (low Mach number approximation)
allowing large density and temperature changes Direct Numerical Simulation mixture fraction / finite kinetics – no soot model Radiative Transfer Equation (non-scattering approximation)
RTE
Finite Volume Method Wideband model ( H2O + CO2 )
NUMERICAL PROCEDURE
INTRODUCTION
EXPERIMENT
SIMULATIONGoalToolDomain
COMPARISON
CONCLUSIONS
Numerical Tool:Variant of Fire Dynamics Simulator (FDS):
transient 3D Navier-Stokes equations (low Mach number approximation)
allowing large density and temperature changes Direct Numerical Simulation mixture fraction / finite kinetics – no soot model Radiative Transfer Equation (non-scattering approximation)
RTE
Finite Volume Method Wideband model ( H2O + CO2 )
NUMERICAL PROCEDURE
INTRODUCTION
EXPERIMENT
SIMULATIONGoalToolDomain
COMPARISON
CONCLUSIONS
Numerical Tool:Variant of Fire Dynamics Simulator (FDS):
transient 3D Navier-Stokes equations (low Mach number approximation)
allowing large density and temperature changes Direct Numerical Simulation mixture fraction / finite kinetics – no soot model Radiative Transfer Equation (non-scattering approximation)
RTE
Finite Volume Method Wideband model ( H2O + CO2 )
NUMERICAL PROCEDURE
INTRODUCTION
EXPERIMENT
SIMULATIONGoalToolDomain
COMPARISON
CONCLUSIONS
Methodology:choice of the iso-contour value?
Sum of volumetric
combustion rate
threshold
Max
10 % of Max
Iso-contour value
COMPARISON
INTRODUCTION
EXPERIMENT
SIMULATION
COMPARISONMethodologyStand-off distanceFlame lengthSoot role
CONCLUSIONS
Stand-off Distance:iso-contours
VOX
VF
COMPARISON
INTRODUCTION
EXPERIMENT
SIMULATION
COMPARISONMethodologyStand-off distanceFlame lengthSoot role
CONCLUSIONS
Flame Length:
COMPARISON
INTRODUCTION
EXPERIMENT
SIMULATION
COMPARISONMethodologyStand-off distanceFlame lengthSoot role
CONCLUSIONS
Flame length:
INTRODUCTION
INTRODUCTION
CURSUS
ENSEIGNEMENTCadreExpériences
RECHERCHECadreExpériences
CONCLUSIONS
Discrepancy Evolution:
COMPARISON
INTRODUCTION
EXPERIMENT
SIMULATION
COMPARISONMethodologyStand-off distanceFlame lengthSoot role
CONCLUSIONS
Discrepancy Evolution:
VOX=150 mm.s-1 VOX=250 mm.s-1
(b)
(a)
characteristic residence time
VOX
COMPARISON
INTRODUCTION
EXPERIMENT
SIMULATION
COMPARISONMethodologyStand-off distanceFlame lengthSoot role
CONCLUSIONS
This study achieved :
coupling of radiative transfer and finite kinetics, leading to flame extinction simulation, thus better flame shape predictions
highlight the soot keyrole in the extinction at the flame trailing edge
This study needs to achieve :
incorporation of a soot model
CONCLUSIONS
INTRODUCTION
EXPERIMENT
SIMULATION
COMPARISON
CONCLUSIONS
This study achieved :
coupling of radiative transfer and finite kinetics, leading to flame extinction simulation, thus better flame shape predictions
highlight the soot keyrole in the extinction at the flame trailing edge
This study needs to achieve :
incorporation of a soot model
CONCLUSIONS
INTRODUCTION
EXPERIMENT
SIMULATION
COMPARISON
CONCLUSIONS
Enjeu: utilisation de l’échelle des temps de résidence pour l’étude de l’extinction de la réaction par les pertes radiatives
Techniques expérimentales
Analyse dimensionnellede la couche-limite réactive:
Foxsox
sf VV~,
,
ττ
Résultats:
fraction volumique de suie mesurée et rapportée à FoxVV
expérimental
théorie
Techniques expérimentalesEchéance: caractérisation des conditions ( Tsuie , fsuie ) dans la zone de quenching Incandescence Induite par Laser Emission/Absorptio
n Modulée
étalonnage
z y
x
z y
x
Enjeu: appréhender la dynamique de l’interaction flamme non- prémélangée / particules
Techniques expérimentales
touverture caméra
flash laser
Résultats:
Echéance:couplage de techniques pour cerner le couplage aérodynamique des flammes / formation des suies
LIF
LII
intensité induite
APPENDIX
X=0,1 X=0,5 X=0,98 X=1,1
Vox =100 mm.s-1
flxX =
Computational Domain:
NUMERICAL PROCEDURE
INTRODUCTION
EXPERIMENT
SIMULATIONGoalToolDomain
COMPARISON
CONCLUSIONS
oijkI
z = 0:u = 0T = Tw
εw = 0,95
y = 0:grad u = 0T = Ta
ε = 1
x = 0:u = Vox
T = Ta
ε = 1
y = ymax:grad u = 0T = Ta
ε = 1
z = zmax:grad u = 0T = Ta
ε = 1
x = xmax:grad u = 0T = Ta
ε = 1
g = 0