Convergence Problem,urgent!!
 

Hello everyone,

I just start my CFD study for a few weeks. Two weeks ago, I finished a prediction of low pressure transient gas jet using Fluent. And the predicted results were in good agreement with the experimental measurements. However, when I began to simulate high pressure transient gas jet, I encountered a convergence problem. I have tried many methods: lower the under-relaxation factors, reduce the time step size, refine the mesh; but they don¡¯t seem to work.. Please give some advice to me! Thanks in advance!

And I have another problem here, propane turn to liquid under pressures more than 0.8MPa when its temperature is 300K. If I am to simulated propane jet with its driving pressure more than 0.8Mpa, when it is injected out, its pressure will decrease obviously and it will turn to gas phase. I don¡¯t know whether the material database include this property for propane. And if it doesn¡¯t, what should I deal with it? Thanks a lot!!