FLOW STRUCTURE IN A FLOODED BALL-BEARING

The flow structure in the confined space between the outer ring, the c age and the balls of a bearing is investigated using a large scale mod el allowing to perform visualizations, by tracer and dot-paint techniq ues, and velocity measurements, by Laser Doppler Velocity (LDV), throu gh the transparent rotating outer ring. The visualization results show , in the region between two consecutive balls, the existence of a reve rsed flow on the cage surface resulting from the aspiration and blowin g effect of the rotation of the balls in their cage housings. Systemat ic measurements of azimuthal velocities in different cross-sections of the gap confirmed the qualitative visualziation findings in laminar f low. For turbulent flow the results show that the extension of the rev ersed flow region is reduced and the reversed velocities are proportio nally smaller as compared to the laminar case.