I am trying to simulate the flow condition inside a Base Transceiver Station, an outdoor shelter used by telecommunication industry.

The computational domain consists of a shelter having fans inside it to circulate the air. Their is no physical inlet or outlet. For my CFD simulation, I can replace fan with the inlet. What do I need to do for the outlet boundary condition?

Thanks

>For my CFD simulation, I can replace fan with the inlet

A regular inlet condition alone won't do it for the fan. The fan introduces momentum and energy to your system, but mass has to be conserved. You might think of a combination of inlet and outlet conditions for each fan, i.e. model the fan as "black box" with specified inlet and outlet conditions.

Or treat it as source term of momentum in the region that the fan occupies.

This is tricky as the fan is likely to add angular momentum as well as axial momentum to the fluid. These 'suggest' a cylindrical coordinate system. If your 'chamber' isn't a cylinder that's coaxial with the fan rotation axis, you'll need to be careful in assigning the momentum creation correctly in the coordinate system you're using.

Good luck.

Mani/Jim,

Thanks for your inputs. My computational domain is almost cubical with various electronic heat sources and PCM heat sinks here and there. The fan is mounted on the ceiling vertically downwards. So, I can put the momentum source at the fan (blade) location.

But I do not know how to do in CFX. Any further help would be highly appreciated.

Amod

I haven't tried to use CFX in 9 or 10 years, so can't help with that. I think there's a CRX user forum here on cfd-online. You might try that.