Flow And Thermal Analysis Of Bearing Spray Lubrication Combining Mechanical Properties And Elastohydrodynamic Theory

Bearing mechanics and lubrication research are mostly carried out separately.The pressure field distribution,film thickness distribution and temperature field distribution from the contact interface can not be obtained,which affects the accuracy of bearing friction heat generation calculation,have an impact on the calculation of temperature field boundary conditions.Considering the severe operating conditions of heavy-load and high-speed bearings,the friction heat source calculation method based on narrow working conditions or empirical formula couldn't meet the analysis and design requirements.Based on this,this paper combines the bearing mechanics model with the elastohydrodynamic lubrication model.The flow field and temperature field simulation analysis of bearings,providing analytical methods for spray lubrication parameter design,heat generation and heat dissipation mechanism research of aerospace bearings.Firstly,the quasi static model of angular contact ball bearing considering the oil film effect is established.The load distribution and motion parameters are obtained by Newton-Raphson method,and the influence of working conditions and structural parameters on it is analyzed.The calculation results are compared with the quasi-static and dynamic calculation results without considering the oil film effect,the results shows that the effectiveness of the method.The calculation method of oil film thickness with bubbles is discussed,which shows that the influence on the mechanical distribution of bearings is small.Then,the influence law of gas content on elliptical isothermal contact lubrication performance is derived.The two-dimensional digital filtering method is used to simulate the Gaussian rough surface,and compare with the deterministic models.Substituting Gaussian surface roughness into the film thickness equation to establish a thermal elastohydrodynamic lubrication model considering spin speed and Gaussian rough surface.The multi-grid integration method and progressive mesh densification method are used to solve the model,and the effects surface roughness and working parameters on the lubrication performance of angular contact ball bearings are analysised.Furthermore,the fluid domain model of the angular contact ball bearing spray lubrication is established.The selection method of the flow field boundary condition is studied.The spray speed,the number of nozzles,the nozzle position and the rotational speed on the lubricant volume,pressure distribution and velocity distribution are analyzed.Sensitivity analysis of the influence of the velocity distribution and the influence parameters of the flow field.Finally,bearing load distribution and velocity parameters obtained by mechanical,friction coefficient and shear stress obtained by elastohydrodynamic lubrication,based on this,the local heat generation method is used to calculate the frictional heat of the bearing,using the heat source as a boundary condition to input the bearing lubrication temperature field model.The distribution of bearing temperature field under different spray speed,number of nozzles,nozzle position and oil parameters was obtained,and the influence law was analyzed.