Starvation Effects on the Hydrodynamic Lubrication of Rigid Nonconformal Contacts in Combined Rolling and Normal Motion

Abstract

The effect of inlet starvation on the hydrodynamic lubrication of lightly loaded rigid nonconformal contacts in combined rolling and normal motion is determined through a numerical solution of the Reynolds equation for an isoviscous, incompressible lubricant. Starvation is effected by systematically reducing the fluid inlet level. The pressures are taken to be ambient at the inlet meniscus boundary and the Reynolds boundary condition is applied for film rupture in the exit region. Results are presented for the dynamic performance of the starved contacts in combined rolling and normal motion for both normal approach and separation. It has been found that during normal approach, the dynamic load ratio (i.e. ratio of dynamic to steady-state load capacity) increases considerably with increase in the inlet starvation. The reverse effect is observed during separation when the dynamic load ratio reduces significantly. The effect of starvation on the dynamic peak pressure ratio is relatively small. Further, it has been observed that with increasing starvation, film thickness effects become significant in the dynamic behavior of the nonconformal contacts. For significantly starved contacts, the dynamic load ratio increases with increase in film thickness during normal approach and a similar reduction is observed during separation. A similar effect is noted for the dynamic peak pressure ratio. Ninety-five cases were run to incorporate the effects of starvation and film thickness on the dynamic load ratio and the peak pressure ratio as obtained in an earlier investigation for fully flooded contacts.