The boundary condition of ventilation fans
 

Dear all,

I am doing a numerical simulation of ventilation flow (with FLUENT) in a closed cabin, i.e., there is no inlet and outlet, the ventilation source is one or two axial fans. I'd like to know how can I specify the boundary condition for the fans, is it enough to give just the fan profile (pressure head vs. flowrate)? If the internal flow is turbulent(max. velocity ~0.5m/s), should I give also the turbulent intensity and length scale as boundary condition? And if yes, how can I determine them because the fan provider gives only the fan charactristic profile (pressure head vs. flowrate)? Which of the turbulence model in FLUENT is the most suitable if there are also some obstacles(electronic instruments) in the cabin? I will first run this simulation in isothermal case but then I should consider also the heat transfer in the cabin(from electronic instruments). Is there any one who has done some simulation of ventilation fans? Any suggestion and information are appreciated and thank you for your kind help in advance. If it's convenient to you, please give me a copy of your post to my email address also, thank you! Regards!

Re: The boundary condition of ventilation fans
 

Sounds to me that Flotherm or that Fluent electronics code would be more appropriate for this level of model. I know that Flotherm has specific axial fan objects that account for all the dominant fan characteristics automatically, even swirl.

Fred.

Re: The boundary condition of ventilation fans
 

Hi Fred,

Thank you for your reply. I don't have access to Flotherm, do you know if Fluent electronics is a standard part of Fluent or an additional part we should order additionally(it seems that in our Fluent package it doesn't contain this item)? If I just have access to Fluent, is there anyone who can give me some infos about how to do this work? Much thanx for your feedback.

Gratefully,

SP

Re: The boundary condition of ventilation fans
 

Both Flotherm (from Flomerics) and Icepak (from Fluent and ICEM) are tailored codes specifically designed for the electronics cooling market. They don't come cheap and are intended to be used by both electrical and mechanical engineers in an industrial setting. I'm sure Fluent itself could be turned to modelling fans but it could well be an arduous task.

Good luck.

Fred.