Study on Mixed Lubrication Performance of a New Type of Multi-Liner Water-Lubricated Stern Bearing Under Complex Working Conditions

Abstract

Due to the incomplete understanding of the mixed lubrication mechanisms of novel multi-layered composite water-lubricated stern bearings under complex operational conditions, this paper addresses the cantilevered offset loading conditions and the multifactorial coupling characteristics that these bearings frequently encounter in such complex scenarios. Firstly, a mathematical and physical model for mixed lubrication within the multi-layered composite water-lubricated bearing-flexible rotor system was established. Secondly, numerical simulations were utilised to analyse the impact of coupled factors such as rotational speed, load, water supply pressure and radial clearance on the mixed lubrication performance of the bearings. Finally, a water-lubricated bearing test rig was constructed to conduct multi-condition and multi-section lubrication performance tests on the bearings. The research findings indicate that under single-sided loading conditions with the same velocity increment, the water film pressure decay rate accelerates from measurement points P1 to P5, with a pronounced decay observed at section P5, with a decrease of 48%. As the rotational speed increases, the squeezing effect diminishes for sections further from the cantilever end, leading to a reduction in water film pressure and alleviation of pressure concentration. Under double-sided loading conditions, the water film pressure in the cross-section at measurement point P2 decreases by 10%, and this trend moderates as the load increases. In contrast, the water film pressure in the cross-section at measurement point P5 increases to 25 kPa, and the circumferential distribution of the water film broadens. Moreover, as the rotational speed increases, the water film pressure decreases and the circumferential distribution of the water film narrows.