Experimental and Analytical Investigation of Performance of Liquid Metal Herringbone Grooved Bearings with Cylindricity Errors

Liquid metal herringbone grooved bearings (LM-HGBs) are customarily used in high-performance x-ray tubes to support the high-speed rotating anode and facilitate heat transfer from the anode to the coolant. This article investigates the impact of cylindricity errors on LM-HGBs performance through simulations and experiments. The analysis considers both the Reynolds equation modified by turbulence and the film equation incorporating cylindricity errors to construct the prediction model of LM-HGBs. An experiment rig was constructed to measure the friction torque of LM-HGBs. The predictions were validated by comparing to experimental results. The pressure distribution was predicted under different cylindricity errors. The test and experimental results demonstrate that cylindricity error impacts the uniformity of groove depth and has a significant effect on the friction torque of the bearings. Theoretical results reveal that concavity and convexity errors alter the pressure distribution and have opposing effects on bearing static and dynamic parameters. Decreasing the ratio of error amplitude to groove depth and the ratio of error amplitude to radius clearance can reduce the effect of cylindricity errors.