Hello CFX users, i have a multiphase problem and i have never used multiphase before i m new to this,and i need ur help in this matter from u CFX guys out there.

Problem Description:

A tank which is full of water and is submerged in water, now what i want to simulate is that tank has an inlet on its upper side ok and has an outlet or drain in the lower side. When i blow air at say some pressure from inlet into the tank which is full of water and i want to remove the water from tank which drains from the outlet. So i want to determine the pressure on the inner walls of the tank due to pressure of air blow and flow rate of water coming out of the tank? I think i have properly conveyed that problem to u guys Its just an example which i want to perform on this CFX software and please guide and tell me can this really be simulated. What should be the boundary conditions for this problem Thanks in advance and ur contribution is really appreciated and respected pls do reply.

Hi Sam, it sounds like you are modelling something like a ballast tank on a submarine ?? To do this you would want to start using the homogeneous multi phase model. This assumes a clear interface between faces. The rate at which the water in the tank comes out I guess will depend upon the pressure of the water surrounding the tank, so a function may be needed to specify the pressure on your outlet drain. Actually you may not need that function, assuming the tank is always at the same depth, then you should be ok.

Robin is the man when it comes to this sort of thing. You may need to add the hydro static pressure to your simulation to get the correct pressure on those inner walls of the tank.

Bob

well thanks alot Bob for ur response,actually my problem is that i m really new to CFX and to be very honest i have not been able to do this simulation, i need ur help in doing this simulation and what will be the boundary condition and how i can model the computational domain. Thanks in advance