T. POINSOT Codes de Combustion - ForeFire API: javascript

108 Pages·2010·2.67 MB·French

T. POINSOT
Codes de Combustion
Lundi 31 Mai 2010, 11h00 – 12h30
Codes for combustion
T. Poinsot1,2,3, F. Nicoud2, B. Cuenot2,
L. Selle1, G. Lartigue2, L. Gicquel2, S. Candel4

and others !
1IMFT, CNRS, Toulouse France
2/CERFACS, Toulouse France
3CTR, Stanford and NASA Ames
4EM2C, Paris
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OUTLINE
The reacting Navier Stokes equations and the codes to
solve them
The differences between RANS, DNS and LES
Computing vortices and acoustic waves in CFD: simple ?
High Performance Computing and combustion
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Which equations ?
Here we will talk only about the compressible reacting Navier Stokes
equations.
Arrhenius reaction rates but usually reduced chemical schemes.
No simplifications using special models (infinitely fast chemistry,
flamelet model etc).
Acoustics included
Full multispecies formulation, no simplification for the state equation,
the variable heat capacities
3 AVBP-course
Thermodynamics: equation of state
A mixture of k= 1 to N perfect gases.
Composition characterized by mass fractions Yk=mk/m
Molar weight of the mixture
with
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EQUATIONS : compressible reacting Navier Stokes
MOMENTUM:
Same as usually.
Except that viscosity is more difficult to estimate:
•  it is a gas mixture with varying composition Yk, k=1 to N
•  its temperature changes significantly
Viscosity = f(Yk,T)
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MASS CONSERVATION: one equation for each species k= 1 to N
! = ! *Y is the partial density of species k
k k
Diffusion Reaction rate
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ENERGY:
Heat flux Reaction rate Radiation
THESE EQUATIONS ARE UNFILTERED, INSTANTANEOUS
THE MAIN ISSUE IS HOW TO HANDLE TURBULENCE !
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Classification générale
LAMINAIRE TURBULENT
Zéro
CHEMKIN: Aurora
CHEMKIN: Aurora
dimensionnel:
T=f(t) Yk=gk(t)
Avec méthode pdf
PREMELANGE
1D: Codes de recherche
Premix
COSILAB
CODES TURBULENTS
Codes de recherche
DIFFUSION
Oppdiff CHEMKIN
8
C est quoi, un calcul 0D ?
Exemple: le temps d’autoallumage
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