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Nijanthan July 16, 2013 03:10

solution is not getting converged
am having pressure inlet of 83 bar,where its inlet diameter is of 9.05mm. also pressure outlet of 43 bar with outlet dia of 2.05mm.
my problem is if i monitor the mass flow rate in inlet it is around e15. because of which my solution is getting diverged and also am having turbulence viscosity limited error. how do i rectify it ???
Note: msh count is of 6.4million and it has interfaces in it.

vasava July 22, 2013 08:40

83 bar (almost 38 atm) and a diameter of mere 9 mm looks an unrealistic problem. What is the application of your problem?

Nijanthan July 24, 2013 04:52

well its kind of water injector. sorry sir cant tel rest of it coz its confidential

vasava July 24, 2013 07:37

Ofcourse with that high pressure you would get high mass flow rate. The turbulence viscosity error is because of coarse mesh, bigger time step or both.

upeksa July 24, 2013 20:35

I'm not sure, but I think that the problem could be that the conditions of pressure-inlet and pressure outlet, it might be too restrictive.
First try with mass-flow-inlet and presure outlet and if it doesn't still work, try mass-flow-inlet and outflow.
Also use the first order discretization and make sure you have set up your case properly, specially make sure your material choice is the correct one.

Best regards.

vasava July 25, 2013 01:42

Still my concern is the enormous amount of pressure and the tiny little outlet. You would need billions of mesh elements just to keep the courant number low.

There must be some other detail you can spare.

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