Learning Forum

[kailash]

Hi everyone. Its mentioned in the Ansys Fluent manual that I should not use outflow boundary condition especially in a multiphase flow. I am using a mass flow inlet and pressure outlet boundary condition. I am running with 1.6 million cells and I am already at 7000 iterations. I am using k-e, scalable wall functions, all second order equation with pseudo transient and time scale factor of 0.05. The issue is I am still facing Reverse flow at the pressure-outlet. When I change to outflow boundary condition, I see that there is no reverse flow. I have extended the outlet so that I can use the outflow boundary condition so that I can assume its a fully developed flow. Please let me know if its okay to use outlfow boundary condition

[Rob]

I would stick with the pressure outlet and look to understand why you have back flow and what it means to your result.

[Fbsl]

Hey kailash, in which section is it written in Ansys Fluent manual that one should not use outflow boundary condition in a multiphase flow?
Sorry, I can't help you with your problem, but this information might help me with an issue I'm facing in my simulation...

[Rob]

Try the User's Guide, there's a whole section on the outflow condition.