Gas turbine combustor modelling - uburned fuel at the outlet
 

Hi everybody,

I am modelling a DLE micro gas turbine combustor using the partially premixed model in Fluent.
I have noticed that using the steady flamelet model with GRI3.0 chemical mechanism the temperature at the combustor outlet is significantly underpredicted. After a short investigation, I found that I have a significant percentage of uburned fuel at the outlet (mass fraction of CH4 at the outlet is about 3e-3 which is very high).
The same problem is present using Chemical equilibrium approach instead of the steady flamelet.

I do not face this problem using the eddy dissipation model (CH4 at the outlet is of the order of e-8, as it should be) and the outlet temperature value is correct.

Any idea on what is going on with the partially premixed model?

Cheers

Andrea