Combustion modelling with energy source
 

Hi,

I want to model natural combustion in a domestic boiler but without using a combustion model. In the flame area I set an energy source and the flow is goint out from a mass inlet face. The problem is that my flow is not turbulent like it should be in reality, and it has a great importance because it occurs in a compact space where the heat exchangers are closed to the flames. I have make a 2D axisymmetric model to see the difference between combustion modelling and only transport modelling and as expected, it affects the heat transfer rate at the heat exchangers. I don't have enough calculation power to run a 3D model with combustion. What can I do to get a realistic modell without using combustion model? thanks