[dibloff]

Hello Analysts

I’m running a complex model in CFX with multiphase, rotating domain and gravity. the domain is initialized with air, and then coolant is being introduced through the coolant inlets. The CFX solver will not run in steady state mode if the gravity vector is perpendicular to the axis of rotation. the ANSYS guys confirmed that this is a solver limitation. I was told it’s the same in fluent too. I want to run a steady state analysis compared to transient, because my fluid time scale is ~4 ms, while my thermal time scale would be in 10’s of seconds.
to simplify the analysis I ventured into using a negative pressure boundary @ the outlet, to “lure” the fluid there, but I’m not sure what should be the pressure I would have to use, since it’s 2 phase flow. the volume does not have a breather hole, or other opening on it. so if I apply a negative pressure boundary at outlet it’ll create a relative vacuum and it’ll facilitate the oil flow from the oil inlet(s).
I’ve done a transient analysis to see what the (stabilized) pressure would be @ the outlet (over a 1 sec run time) but it did not converge. I’ve done numerous small scale studies to investigate this but at the end of the day I’m not sure I can believe the numbers.
I’m wondering if anyone has a better idea on how to tackle this problem.
Any suggestion is appreciated,
thanks.

A.