Mixture model with one compressible fluid phase

oden

Hello,

I try to inject a compressible gas into a vessel filled with a hot liquid at high density. The inlet conditions of the gas are pressure = 4.5 bar, temperature = 229 K and density = 9 kg/m3. The inlet Mach number is about 0.95. The gas expands (jetting) and forms a bubble column, the bubbles finally rise and induce the motion of the liquid phase.

It was suggested by FLUENT to use the mixture model (gas: primary phase and ideal-gas law; liquid: secondary phase). Other settings are SKE model, Standard wall functions, initially low relaxation factors (pressure, momentum and volume fraction 0.2 - 0.3)and first-order upwind discretisation. The time step size is 10-5, but in any case, the solution does not converge. Smaller time step sizes show the same behaviour.

Has anybody experience with similar flow conditions?

Thank´s a lot for your response,

Juergen