Numerical analysis on cavitation of LNG in micro clearance of self-lubricated journal bearing

In the Liquefied Natural Gas (LNG) transportation and storage, pump is required to transport the processed fluid. In order to meet the requirements of hydraulic head, tightness and purity, a high speed full-cryogenic centrifugal pump using LNG as self-lubricant is under development. To reach the high pump head, the centrifugal LNG pump must be working at high rotational speed. In self-lubricated bearing, sub-ambient pressure will be generated due to the hydrodynamic effect. Hence, cavitation is most likely to occur in micro bearing clearance lubricated with near-saturated LNG. In order to mitigate cavitation in micro bearing clearance, thermodynamic effect in cavitation-flow is focused on. Numerical analysis of LNG lubricated herringbone bearings is carried out and the bearing characteristics are analysed. Furthermore, liquid nitrogen(LN2) test is performed for similarity experiment to verify the simulation and the feasibility of structural optimization.