Shawn Ren

Thank you for your prompt response. For my own case, I set the y+ as about 50, and I also tried coarser or finer mesh. Once the fluid was heated to saturation temperature, the case would diverge soon. 

For the tutorial case, technically speaking, it's from the Fluid Dynamics Verification Test Cases, I did not know the y+,  but the number of the radial grid nodes is indeed very small.  It was running with constant properties at a certain pressure point. I guessed it might be sensitive to the fluid properties, however, the model corrections are tuned fine for that setup in the verification case, the current situation is that only one value change causes the result to diverge.

Of course, I learned the verification case for getting some clues for my own setup, could you please give me further suggestions now? Thank you.