spray and combustion with EGR
 

I am running diesel spray and combustion model.Unpremixed/Diffusion, EBU LATCT. I tried to calculate NOx concentration with EGR rate 5%, 10%, 15% and 20%, setting respectively initial conditions for air with CO2 concentration. However, for all of these models, I get the same temperature and NOx values. I checked all time steps, but either the values are the same, or they differ very little. For example, if EGR is 20%, NOx reduction is supposed to be about 50%. But, I can not get even close to this fact. Perhaps, I need to use different model settings. Does anybody know this problem? Please advise.

Regards