Structural selection of liquid hydrogen lubricated herringbone spiral-grooved thrust bearing considering viscous dissipative heat

Abstract

Spiral-grooved thrust bearing (SGTB) is one of the important kinds of supporting component in high-speed rotating devices. The high shearing rate of SGTB can produce a large amount of viscous dissipative heat, which causes a temperature rise. Dynamic pressure effect induces pressure variation in the herringbone SGTB (HSGTB). When liquid hydrogen (LH2) is used as a lubricant, cavitation caused by lower pressure and higher temperature can result in lubrication failure. Especially, the cavitation of LH2 is more prone to occur because of its small temperature difference between the triple point and critical point, and the smaller supercooling degree. The influence of thermal properties on the phase transition process of LH2 is more significant. In this paper, the thermal and mechanical performance of three different structures of LH2 lubricated SGTB is compared by considering viscous dissipative heat. Herringbone SGTB is proposed for better performance and feasibility of its application in LH2 lubrication. The static performances of HSGTB such as load capacity, friction torque, cavitation rate, average temperature, and heat flux have been evaluated numerically by introducing the cryogenic cavitation model. The orthogonal sampling method and range analysis are used to optimize the HSGTB structure. Compared with the original HSGTB, cavitation rate and temperature rise are significantly suppressed in the optimized HSGTB. In addition, the load capacity is also improved effectively at high rotational speed, which is expected to be applied to high-speed centrifugal pumps.