This paper investigates the windage power losses generated by spur gears rotating in pureair by using a computational fluid dynamics (CFD) code. The three-dimensional simulationsare at first validated comparing CFD predictions with the power losses measured in similarconditions from other investigations. The volumetric flow rate which is expelled by theteeth is then analysed, and a correlation which is based on a classical approach used inturbomachinery is finally proposed which makes it possible to estimate windage losses forspur gears. It was observed that this latter approach seems satisfying since theformulation of the volumetric flow rate which is employed in the model is appropriate toeach gear.
