The Effect of Star Shaped Dimples on Sliding Surfaces under Hydrodynamic Lubrication

Abstract

Tribological behaviour of sliding surfaces with star shaped micro-dimples on one of the surface is reported. One wall is smooth and sliding on the other fixed dimpled wall with constant velocity. Effect of star shaped dimple and oriented star shaped dimple has been compared with circular shaped dimple for hydrodynamic pressure generation and tribological behaviour. Effect of dimple depth, dimple area density and sliding speed on tribological behaviour were also analyzed. The results demonstrate that an unconventional star-shaped and orientated star-shaped dimple produces a larger net hydrodynamic pressure in the fluid domain and provides better stability between the sliding surfaces than a circular-shaped dimple. It is shown that geometric parameters like dimple depth and dimple area density and operation parameter like sliding speed affects the hydrodynamic average pressure and tribological behaviour of sliding surfaces significantly. The experimental findings validate the analytical and CFD findings.