COMBINED INFLUENCE OF JOURNAL MISALIGNMENT AND SURFACE ROUGHNESS ON THE PERFORMANCE OF AN ORIFICE COMPENSATED NON-RECESSED HYBRID JOURNAL BEARING

摘要

The combined influence of surface roughness and journal misalignment on the performance of an orifice compensated hole-entry hybrid journal bearing system is theoretically studied. The analysis considers the average Reynolds equation for a rough surface for the solution of the lubricant flow field in the clearance space of a journal bearing system. The bearing performance characteristics are presented for the various representative values of surface roughness parameter (∧) and surface pattern parameter (γ) for a concentric design pressure ratio β*=0.5. Performance is also compared to capillary and constant flow valve compensated bearings. The computed results indicate that the effect of journal misalignment is to lower the value of the minimum fluid-film thickness of the journal bearing system while the effect of surface roughness is to partially compensate this loss. For the chosen values of journal misalignment parameters (Φ,δ), the constant flow valve compensated symmetric journal bearing configuration with longitudinal roughness pattern (γ- 6) shows an improvement of around 20% in the value of stability threshold speed margin.