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 CFD Student November 27, 2005 06:52

Simplest combustion model

Dear CFD People,

I wrote density-based, Favre-Averaged Navier-Stokes solver based on 2-d finite volume cell-centered scheme with central averaging (JST) and upwind schemes (van leer, Roe FDS, E/H-CUSP) using dual time stepping method for simulating unsteady flows with Weiss&Smith preconditioner for computing flow in the incompressible limit. I also implemented Baldwin-Lomax and Spalart-Allmaras models for turbulence.

Although I am completely new in combustion modeling, I am willing to extend my code for simulating combustion and I want to start with the simplest model in 2-d. I heard "Arrhenius model" is the simplest one? is it true? Any help is greatly appreciated.

Best regards.

CFD Student.

 Guillaume November 28, 2005 10:19

Re: Simplest combustion model

It depends on anybody the question is asked to.

My opinion is that the equilibrium, also called `mixed-is-burned' model is the simplest one (even from a coding and numerical point of view).

 versi December 2, 2005 09:54

Re: Simplest combustion model

Arrhenius model refers that the reaction rate constant is expressed as k= A T**B exp(-C T), where A,B,C are constants and T are temperature in K. The rate constat only depends on T.

 David December 2, 2005 17:00

Re: Simplest combustion model

CFD Student,

You might try implementing an eddy-break-up(EBU)/finite rate model, though it is generally used with two-equation turbulence models when applied to Reynolds Averaged equations.

It should be fairly straight forward to code and more stable than a finite-rate model.

Dave

 CFD Student December 3, 2005 08:35

Re: Simplest combustion model

Thanks a lot for all. I'll try to do my best.

 Gordan Feric December 6, 2005 10:54

Re: Simplest combustion model

Hi there:

If you are interested in complex chemical compositions for combustion products based upon the chemical equilibrium calculations, check out http://members.aol.com/engware where you can find a sample temperature-pressure physical properties and composition matrix for a given chemistry case.

Thanks,

Gordan

 balu December 7, 2005 04:23

multi phase model-query

Subcooling of Refrigerent(From 79 to 60 K) tanks of Liquid nitrogen by using fluid dynamic pump (Ejectors) I have modelled the above 2D axis symmetry with Multi phase model.Liduid tank with vapor is separated by interface over the tank the ejector assembly is mounted. Is it the above model"ll give better result,then i wish to know inital vapor condition & boundary conditions of the above domain in transient analysis.

Thanks.

 Alexey Evlampiev December 13, 2005 18:20

Re: Simplest combustion model

Dear CDF Student,

To compute chemical reacting flows you can use C-MECH C++ open sources from

http://w3.wtb.tue.nl/nl/organisatie/...gy/flamecodes/

As you can find there C-MECH is an ANSI C++ source code format for chemical reaction mechanisms. In contrast to usual text-formats, the C-MECH-library provides the user with a number of functions calculating thermodynamic, chemical kinetic and molecular transport properties. Hence, the C-MECH formatted reaction mechanisms can directly be applied in simulations and analysis.

C-MECH can be used to evaluate:

* Chemical reation rates

* Thermodynamic characteristics

* Molecular transport coefficients

Regards

Alexey

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