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.

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).

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.

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

Re: Simplest combustion model
 

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

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

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.

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