The turbulent flow field at the rotor-stator gap entrance of a generator was investigated numerically. Predictions of the fluid dynamics characteristics for the present problem were made by adjusting boundary pressure conditions to match the prescribed flowrate allocation. The velocity field and pressure distribution at the rotor-stator gap entrance were presented. The mean values of pressure and velocity, obtained by integrating the local values across the flow cross-sectional lines, were applied to calculate pressure loss coefficient ß at the gap entrance.
Results show that because of the complex geometry at the air gap entrance and flow splits through the stator cooling ducts, the display of ß is rather complicated. Rotating body windage losses for the rotor and retaining rings were determined from calculated friction factors on these surfaces.