Estimating flow rate from fan blade speed and angle

[XIX]

Is there an equation with which I can estimate the flow rate a fan will generate at a set diameter, speed and angle of the blades? Assume that this is a simple box fan that you would put in your window.

I'm assuming that you would have to determine the axial speed of the air given the angle and rotational speed. Then multiply that by the area.

 

[russ_watters]

The angle isn't constant along the span: you need pitch, which is essentially the distance forward it would move if rotated once through jello.