Multiphase CFD in Enclosed Space (no inlets/outlets)

[minger]

Hi guys, I have a co-worker here who is stuck on a problem, and I cannot give him much help either. He is trying to model a multiphase flow with no inlets or outlets. The problem is essentially a rotating cylinder inside of a pipe that is sealed on both sides. Assume that the pipe is half filled with water.

That's it. We are trying to do this in CFX, but having difficulty determining what, if any, boundary conditions can be applied. The Ansys people are of very little help, it any. Any suggestions?

 

[Mech_Engineer]

What exactly are you trying to solve for? Heat transfer? Fluid velocity? When you say multi-phase flow, are you literally trying to keep track of two fluid vapor phases? Do you really have to solve this problem using CFD?

It's possible CFX is not the proper solution for your problem. There will most certainly be much more than boundary conditions that have to be nailed to to get the problem solved; perhaps you should find a professional consultant?

 

[minger]

By multiphase, I actually mean non-mixing water/air (sorry about the confusing). The cylinder inside is spinning and throwing water on the top of the chamber. The problem that we are trying to solve is related to heat transfer, but for the time being, just getting a simplified model to run would be nice.

I have found literature related to this problem, but the spinning cylinder is always in a simple channel flow with easy inlet and outlet boundary conditions. I have just never run into a case where there are no inlets or outlets. I'm not sure how to approach the boundary conditions.

 

[Topher925]

Does the Ansys model require your system to be open? I don't have much of any experience with CFD but if this is the case could you possibly just assume a very small amount of flow through the system? So small that as far as accuracy is concerned, the system can be considered closed?