Learning Forum

[w BC]

Hello, the simulation model I built use density-based, SST K-w model, the material used in my model is real-gas-nist, the inlet and outlet pressure boundary conditions, and the operating pressure is 0.The maximum Mach number calculated by the pressure base model is 0.8.I would like to know how to solve the hybrid initialization calculation done, but fluent can't continue anything.

[Rob]

Hybrid initialisation is failing, or something is/isn't happening after hybrid initialisation? If the operating pressure is zero what are the boundary pressures set as?

[w BC]

The model  is an air valve, which has only one inlet and one outlet. The inlet is set as 0.4MPa for pressure inlet and 0.04MPa for pressure outlet.

[w BC]

Thank you for your response. I found that when I set the material to water vapor, the initialization was done and I could continue. Is it because I set the material to real-gas-nist and I didn't set the boundary conditions properly?How should I set the corresponding boundary conditions？

[Rob]

Boundary conditions are just that, the values at the boundries. The initial conditions are also exactly that, they are the cell values at that instant. If you set the whole domain at 0.4MPa what's stopping the region downstream of the valve trying to flow to 0.04MPa instantly? 

[w BC]

The valve acts like a faucet, with the spool blocking the flow

[Rob]

Yes, but now plot t=0 and tell me what the flow is going to do. 

[w BC]

[Rob]

And the CFD fields at that time?