How to calculate air volume of a fan using pressure?

[Raphael Gonzalez]

How can you calculate air volume in cubic feet per minute through a fan when the only data available is pressure drop and fan diameter?

For example, How many cubic feet per minute of air is a fan blowing if it has a diameter of 20" and a pressure drop of -50 pascals?

 

[russ_watters]

Welcome to PF!

That's pressure rise you mean, but sorry, that isn't enough information to determine the airflow.

 

[rcgldr]

Generally there's a pressure jump (with little change in speed) of the affected air as it passes through the plane of the rotating fan. There are related NASA articles about propellers which should allow you to solve for velocity at the fan (and therefore volume flow at the fan), ... , some what idealized. Assume that V₀ is zero, and that density is constant.

http://www.grc.nasa.gov/WWW/K-12/airplane/propanl.html

http://www.grc.nasa.gov/WWW/K-12/airplane/propth.html