Flow Distribution for 850m^3/h Fans in Electrical Machines

[Edwin_Sun]

Hi Guys,

I want to use a fan which can move air up to 850m^3/h to cool my electrical machine. I mount the fan at one end, so the air can flow through the stator ducts, rotor ducts and the air-gap. How will the flow distribute among the stator ducts, rotor ducts and the airgap? Are there some equations?

If the flow distribution is known, flow average velocity can be calculated, then Re and the convection heat transfer coefficient h and finally the temperature distribution of the machine can be got by the finite element analysis.

Thanks in advance!

 

[ank_gl]

The flow pattern will entirely depend upon the geometry it is flowing through. Once the geometry of flow path is known, an accurate flow pattern can be developed.

 

[Edwin_Sun]

Thanks for your reply, ank_gl!

There are also some other questions.

The rotor is rotating in high speed and the speed is not constant. There are a lot of slot openings in the air-gap, and when the rotor rotating, they will cause resistance to the air flow. This may cause a decrease or increase in heat transfer compared to smooth air gaps. I read a lot of papers written around 1990s about such kind of problems, and nobody gave a detail model or accurate conclusion. I can't find such kind of papers written recently, it seems people have lost interest in it. Now, I want to learn the principle behind this.