Convergence in multicomponent flows
 

I'm running a steady state CFX simulation of a multicomponent flow. The objective is to see the variation of CO2 concentration and the temperature distribution in a living room that has some sources of CO2 and heat energy.

Therefore the fluid in the room is modeled as a mixture of CO2, N2 and O2.

The H - Energy equations of N2 and O2 are struggling to converge ( 1.E-04 is the RMS residual target set).

The convergence is however better in the rest of the equations and also the flow imbalances seem to be fine.

The SST model is used for turbulence modeling and the thermal energy model is used for heat transfer.

Could some one please suggest me a way to improve the convergence of the H - Energy equations of N2 and O2

Have you covered the basics here:

http://www.cfd-online.com/Wiki/Ansys...gence_criteria