Selecting a fan (CFM)

Step 1. decide air speed required (desirable air speed to be decided by thermal design and verified by simulation/test)

: ie 2.17 m/s

Step 2. locate vent size (assume fully open vent)

: ie 50 x 50 mm2  = 0.0025 m2

Step 3. calculate required CFM(cubic feet per min)

: ie 2.17 m/s * (50 x 50 mm2) = 0.005425 m3/s = 0.3255 m3/min = 11.50 ft3/min, CFM

 

*reference 

https://www.eetimes.com/document.asp?doc_id=1276676