振动冲击对海水润滑塑料轴承时变热弹流润滑的影响

摘要

建立了冲击载荷作用下综合考虑热效应和时变效应的海水润滑塑料轴承弹流润滑数学模型；利用压力求解的多重网格法,弹性变形的多重网格积分法及温度求解的逐列扫描技术数值模拟了连续冲击载荷作用下海水润滑膜压力及膜厚的分布；对比分析了正弦周期脉冲及三角形周期脉冲作用下的润滑膜中心压力、中心膜厚及最小膜厚随时间变化的特性；讨论了载荷幅值及脉宽对润滑膜特性的影响.数值计算结果表明,压力的变化周期同载荷的一致,膜厚的变化滞后于冲击载荷及压力的变化；随载荷幅值的增大,压力和膜厚的振幅增大,中心压力的对称线下移,相应膜厚的对称线上移；随脉宽的增大,中心压力的最大值变大,最小膜厚的最小值变小.%A numerical model of elastohydrodynamic lubrication considering thermal and transient effects on seawater-lubricated plastic bearings subjected to impact load was built.The distributions of lubricating film pressure and film thickness were obtained by numerical simulation by using the multi-grid method for pressure,the multi-integration method for deformation and the column scanning method for temperature rise.The time variation characteristics of central pressure,central film thickness and minimum film thickness were analyzed with the bearing subjected to continuous impact loads,such as repeated sine pulses and triangular pulses.The influences of load amplitude and pulse width on pressure and film thickness were discussed.Numerical results reveal that the period of pressure variation is the same as that of the impact load,but the fluctuation of film thickness lags behind the fluctutations of load and pressure.With the increase of load amplitude,the amplitudes of pressure and film thickness increase,the symmetric line of central pressure moves down and the symmetric line of film thickness moves up.The maximum value of the central pressure becomes higher,and the minimum value of the minimum film thickness turns to be smaller when the pulse width increases.