Pressure Drop at entrance of a rotor-stator.
 

Hi, My problem is to estimate the pressure drop at entrance of rotor-stator of electric motor. The flow comes in over end turn of the electric motor and goes into the rotor-stator air gap and leaves through the other end. The flow volume over the end-turn is very big as compared to rotor-stator air gap of 0.06 inches. I can find equations for sudden contraction of pipes, i.e for finite diameter to finite diameter...which is not my case.

And from this website, pressure drop can be calculated for sharp edge entrance (i don't know what equations they used) http://www.pressure-drop.com/Online-.../pda/0201.html

But, again this is for a round pipe. My case is entrance pressure drop for an ANNULUS!! How do I calculate this? Do I need full fledged CFD to find this out.

Second question Making the problem more complicated, because the rotor is rotating hence, the pressure drop in the channel will be more than estimated drop from Darcy's equation.

Please advice.

Thank you. Resnick