Impact of journal shape error on double layer porous journal bearing with non-Newtonian lubrication

Abstract

The accurate prediction of bearing performance is significantly impeded by geometric imperfections of the journal, such as bellmouth and circularity errors. Smooth journal surfaces without geometric irregularities are challenging to achieve for numerous reasons. However, in actual practice, Journal/bearing surfaces typically exhibit surface profile variations, particularly following machining. In recent times, non-Newtonian lubricants have come up in a big way application concerning fluid film journal bearings. The performance of fluid film bearings is significantly impacted by the geometric imperfections of journal (i.e., Bellmouth & Circularity errors) and behavior of non-Newtonian lubricants. This study analyzes the combined effects of cubic law lubricant behavior and geometric imperfections of the journal (i.e., Bellmouth and Circularity errors) in order to conduct a numerical simulation of a double-layer circular porous hybrid journal bearing (DLCPHJB). This investigation examines the interactive effects of bellmouth and circularity errors, permeability parameter, and non-linear factor on the behavior of DLCPHJB. The finite element technique is employed to resolve the modified Reynolds equation for a DLCPHJB. The numerically simulated results indicate that the stability threshold speed is enhanced by accounting for the impacts of circularity error, and frictional torque is reduced by the bellmouth error. This study also shows that the DLCPHJB outperforms the single layer circular porous hybrid journal bearing (SLCPHJB).