[SergeyNikolayev]

Greetings,

I have a problem with non premixed combustion understanding.

In our university we have home cfd code. In my phd work I need to create module to compute cases with non premixed combustion using PDF approach.

I create subroutines to transport mixture fraction and variance and interpolate scalars from prebuilt table (at the first I use external table with density, temperature, enthLpy and species as functions of mean mixture fraction and variance).

It is written in papers that in case of adiabatic non premixed combustion with infinitely fast kinetics the temperature, density and species are functions of only two arguments (f,f''). In my case connection with NS solver is the following: at the NS step I replace temperature and Cp from field with values from table. Density is computed from ideal gad law. Then I compute turbulence and mixture and variance transport.

I try to simulate methane jet combustion. My problems are the following: 1. Velocity does not grow near flame region as in experiment
2. Temperature is constant in places where mixture fraction is equal 1 or 0.

I try to use commercial code with adiabatic non premixed model options to run the same case. Results look reasonably: temperature grows near flame region and it can change even in places with constant f and f''.

I think in my case connection with NS solver is incorrect because temperature is function of only mixture fraction and according to prebuilt table can not change in some regions but I do not know how to change it.

Does anybody have experience in this field?

Thanks for any comments.