Combustion over water Help!!!!
 

Hi there,

I am relatively new to Ansys and CFD in general and am having big problems with setting up a transient methane-oxygen combustion system over a free surface of liquid water on CFX.

I am trying to model both the liquid and gas phases and couple the two to determine evaporation rates and convection cells in both phases.
To start off I only have a simple 2D channel with free-slip walls everywhere except an opening at the end. I know its inaccurate but for the sake of computation time I am using the eddy dissipation and k-e models for combustion and turbulence respectively.

The system works without any ignition source present; the combustible atmosphere exists above the liquid surface. However, when I try to introduce a point energy source to ignite the mixture, the solver crashes on the first iteration loop every time.

Advice would be greatly appreciated!
Thanks

Does the free surface move? Have waves? Splashes, foam, bubble entrapment or anything like that?