Air delivery rate for BLDC motor fan


I have a BLDC motor fan whose speed (in RPM) and dimensions are known. How can I calculate the air delivery rate of the fan at a particular speed? I want the formulae for knowing how much air is delivered by the fan.

Best Answer

Calculating air delivery against fan speed is tricky fluid dynamics.

At base though, air volume per unit time is proportional to fan speed (in the operational region of the fan). So you usually get a measurement at a particular speed, and calculate pro-rata.

Have a look at for fan laws for more information.

Here's a blog post about it from a fan company which should help understand it.