Study On Mixed-lubrication And Dynamic Wear Performance Of Water Lubricated Bearings Under Various Working Conditions

Research subject derives from national defense basic scientific research project“Study on self-lubrication modification of rubber interface of water lubricated bearing and its super lubrication mechanism with Si3N4”,project from Naval University of Engineering “Design and prototype development of water lubricated bearing”.Compared with normal oil lubricated bearings,water lubricated bearings have a series of advantages.However,with the increase improvement requirements of working environment and performance,more stringent requirements are put forward for the lubrication performance and working life of water lubricated bearings.This paper comprehensively applies the coupled analysis methods of fluid mechanics,tribology,elastic mechanics and etc.To analyze the mixed lubrication characteristics of water lubricated bearing under the conditions of multi-media coupling including interface roughness,elastic deformation,journal deflection and complex working conditions,and reveals the wear characteristics under mixed lubrication.A transient hydrodynamic Reynolds equation model with Patir Cheng flow factor is used to predict the time-dependent performance of mixed elastohydrodynamic lubrication.An improved Archard model based modification design method for misaligned water lubricated bearings is proposed,which takes into account the variation of water film thickness under mixed elastohydrodynamic lubrication.Based on the concept of fatigue,the Archard model is extended to predict the time-varying wear.The transient contact pressure,wear depth and wear volume of under ideal and misaligned conditions of the water lubricated bearing are simulated and analyzed,and the influence of misalignment on the performance of the whole bearing is revealed.At the same time,the influence of various parameters on the performance of the water lubricated bearing is studied through parametric research.Finally,in order to verify the applicability of the modification design,the lubrication bearings under misaligned and profile design case are compared.The applicability and correctness of the profile design method are verified through the study of the modification coefficient.Through the simulation data,it can be seen that the profile design improves the performance of the water lubricated bearing,and makes the water lubricated bearing work stably for a longer time under more severe conditions.The specific research contents are as follows:(1)Based on the transient Patir Cheng average Reynolds equation,Based on the average Reynolds equation of Patir-Cheng,this chapter derives the Reynolds equation of water lubricated bearing under multi-parameters such as coupling surface roughness and flow factor,which solves hydrodynamic lubrication,rough interface contact,elastic deformation.Finally,a numerical calculation model of the mixed lubrication and wear performance of water bearing with integrated factors considering elastic deformation,interface contact,journal deflection and complex working is established.(2)According to the working condition requirements of water lubricated bearing,in order to obtain better performance and applicability,after considering the performance parameters of various materials,the polymer plastic material is selected as the bearing material.The multi-field multi-factor coupling lubrication calculation program for the water lubricated bearing is developed,and the mathematical model and the numerical method are verified by comparison simulation.Finally,the optimal number of grids is determined by considering the convergence speed and calculation accuracy.(3)The numerical solution of mixed hydrodynamic lubrication and transient wear of misaligned water lubricated bearings and ideal case are developed.The research of effect of different load,clearance,misaligned angle,rotating speed and other conditions on the lubrication performance and wear of water lubricated bearings are also developed.The performances of water lubricated bearings under misaligned and ideal conditions are compared,and the significance of misalignment for mixed lubrication and transient wear is revealed.(4)Based on the coupled numerical calculation model of water lubricated bearing after profile design,the dynamic pressure distribution,contact pressure distribution,elastic deformation distribution,wear depth and wear volume of water lubricated bearing under the profile design and misaligned condition are analyzed.The influence of profile design on various performances of water lubricated bearings is revealed.The research shows that the profile design improves the capacity of the water lubricated bearing,and reduces the edge wear and wear volume of the water lubricated bearing,which greatly improves the lubrication and transient wear performance of the water lubricated bearing.So,profile design provides a method for the performance optimization of the misaligned water lubricated bearing.