A Research On The Characteristics Of High-speed Cylindrical Bearing Affected By Cavitations And Thermal Effect

In the era of rapid development of rotating machinery,the research on the characteristics of bearing is becoming more and more important.Sliding bearing is widely used in high-speed rotating machinery,which has a series of advantages such as high precision,strong bearing capacity,good impact resistance and so on.In the sliding bearing work,the high speed will make the friction power increases sharply,resulting in the lubricating oil film temperature field and viscosity field distribution more and more uneven.At the same time,pressure change,high speed and other factors will lead to the gas dissolved in the lubricating oil releasing,or make some of the liquid oil change into oil vapour,which will lead to cavitations.Therefore,taking the influence of cavitations and thermal effect into account,the characteristics of the bearing oil film are closer to the actual oil film characteristics.In this paper,the hydrodynamic cylindrical bearing and the deep/shallow cavity hydrostatic cylindrical bearing are studied under the premise of considering cavitations and thermal effect.The relevant mathematical model is established and the finite difference method is used to solve the model.The pressure distribution,density distribution and temperature distribution are obtained,and then the characteristic parameters of the oil film are calculated.firstly,the density model and Reynolds viscosity-temperature model of the gas-liquid two-phase flow are introduced.Reynolds equation and energy equation with variable density and viscosity are established.The corresponding boundary conditions of the oil film solution area are also set.Secondly,the finite difference method is used to discrete the differential equations.Then,the pressure,density,temperature and viscosity of the lubricating oil films with different gas content,different speed and different eccentricity are obtained by the relaxation iterative method.Furthermore,the static and dynamic parameters of the oil film are analyzed,and the variation rules of the characteristic parameters are obtained.The results show that the cavitations and thermal effects will reduce the oil film pressure peak of the cylindrical sliding bearing,and the cavitations will lead to the early failure of the oil film of the hydrodynamic cylindrical bearing.Cavitations and thermal effects have a great effect on the static and dynamic characteristics of the cylindrical sliding bearing.With the gas content,the rotational speed and the eccentricity larger,the influence is more obvious.The effect of thermal effect on bearing capacity and friction is larger,and the effect of cavitations on the lateral flow is larger.The conclusion obtained in this paper provides a theoretical reference for design and performance analysis of cylindrical sliding bearings under the influence of multiple factors.