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How to calculate air velocity in a fan and what data should I know ?

So if I have a fan motor, fan blade and a battery, what data should I get from these items ?

I think I will need to know the number of turns per second. How can I determine it ?

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If you can find the power generated by the motor, you can use $W=\Delta k$ to find the velocity. Unfortunately I don't know of a way to find the power generated by the motor. –  udiboy1209 Jul 30 '13 at 12:27
    
It's an engineering problem with many variables. The subject you need to look up is propeller fans. –  Mike Dunlavey Jul 30 '13 at 21:11
    
The term for "number of turns per second" in physics is frequency. –  Constantine Aug 3 '13 at 19:17
    
If you actually have the fan you could use a Anemometer –  Michal Jan 26 '14 at 19:42

1 Answer 1

You can calculate air velocity as v = f/A where f=volumetric air flow and A = cross-sectional area of the air passage. Also, you have m=p*f, where m=mass flow rate and p=air density. Here 1 it says that "By conservation of energy, the energy consumed in rotating the fan is the same as the energy required to deliver the air: Pfan ∝ υ"

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