[Shamoon Jamshed]

Dear Friends and CFD Experts,

I am modelling a problem, which in my view, can be solved through VOF technique. I am modeling a cylinder which is enclosed from all sides with a small opening at the end and at the top. The cylinder is assumed to contain all the liquid Oxygen but just initially a patch of N2 that is at 90 bar and 300 K. So I introduced a patch of N2 as secondary phase in Fluent. O2 is liquid and is at 60 bar pressure with 80 K temperature. So the pressure of N2 must be pushing O2. Assuming that opening is 20 mm the mass flow rate of O2 should be 10 kg/s. The inlet mass flow rate should be determining/set that gives such a mass flow rate of O2.
1) I have problem in simulating using VOF:
(a) the pressure I specify in mass flow inlet, has not been shown anywhere in the simulation when I initialized from mass flow inlet. When I initialize the solution from m.f.i, it shows 60 bar everywhere which is pressure of O2. If I patch pressure for N2 as 90 bar, the solution diverges.
(b) Technically, the whole tank must get emptied in around 33 seconds and thats not happening. I get half tank filled with N2. (density =1100 , volume = 0.3 m^3 so m = 330; with 10kg/s we should get a time of 33 sec, please correct if I am wrong).
(c) The surface tension of liquid O2 is not known.
Please help me in this regard. I am in serious trouble.

[Shamoon Jamshed]

Please help! its my research work and I am really stuck!