UDF_CH4 combustion
 

Hi!

I´m a beginner in UDF´s. I´d like to create one UDF to simulate a methane combustion (CH4 + 2O2-->CO2 + 2H2O).

The reaction mechanism is (-R_CH4)=k1*YCH4^0.72*e(k2/T)[mol/s·m3] where K1 and K2 are constants, T is temperature and YCH4 is the molar fraction of methane.

can anybody help me?

thank you

Re: UDF_CH4 combustion
 

You probably already realize that UDFs are quite time consuming - especially if you are just getting started.

Why don't use just use the framework already built in to Fluent to do an Arrhenius rate reaction with the species transport equation?

Re: UDF_CH4 combustion
 

I tried it.

First of all, I simulated de methane combustion with the reaction mechanism that FLUENT supplies.(with the Arrhenius parameters). Then, with this outputs I tried to simulate the reaction "on my own" deselecting the reaction option in boundary conditions and selecting the sources option. Results were similar, but now I have to solve the combustion with that chemical kinetic equation and it seems that UDF´s are neccesary...What do you think?

Thanks for your time.

Re: UDF_CH4 combustion
 

You should use the UDF macro DEFINE_VR_RATE( name,c,t,r,mw,yi,rr,rr_t). Follow the example in the UDF manual, it's not very complicated.