Boussinesq approximation in closed system

Nitesh

Hi all

I have to simulate a buoyancy driven flow inside spherical vessel. My task is to calculate heat transfer through walls of closed spherical vessel. The wall temperature are at 300 K and the fluid is filled at 310 K at operating pressure 5bar. There are no pressure, velocity boundary conditions.

Kindly let me know

1. Can I use Boussinesq approx to calculate heat transfer from wall in closed system? (We have neglected radiation and conduction. .

2. If unsteady state analysis of this problem is possible? I tried the unsteady analysis but its taking lot of time about 17 hrs and still could not reproduce the experimental results.

Thanks in advance