Analysis Of Oil Penetrativity On Jet Lubrication For Transonic Flow Rolling Bearings

With the development of science and technology,high speed machine tools and aerospace engine technology are developing continuously.As the key parts of these machines,rolling bearing is facing the challenge of high speed,high temperature and heavy load.This makes its use of increasingly demanding performance requirements.How to lubricate effectively is the most important to meet these requirements.Because of the advantages of simple system,easy control,good lubrication and cooling effect,Oil injection lubrication has been widely used in high speed rolling bearings.With the increase of the speed of the high speed rolling bearing,the inner and outer rings of the bearing will form the high speed air flow.Transonic flow phenomenon will appear between the bearing rings of high speed bearing,the lubricating environment becomes very complex.In order to be more effective for the lubrication of the transonic flow bearing,the penetration mechanism of transonic bearing lubrication research is necessary.Based on computational fluid dynamics,this paper studies the characteristics of the gas flow field in the rolling bearing ring.The mathematical model of gas liquid two phase flow is established by the initial boundary of gas flow field.This paper uses CFD software to simulate the movement process of rolling bearing lubrication of transonic flow and Explore the penetration mechanism of rolling bearing in transonic flow lubricating oil.In this paper,the gas flow is calculated and analyzed.The velocity characteristics and pressure characteristics of the gas phase flow field are analyzed,and the factors that hinder the oil entry are discussed.From the simulation results,we can get the initial boundary of the gas-liquid two-phase flow.Then,the mathematical model of gas-liquid two-phase flow field is established.According to the initial boundary provided by the gas flow field,several three-dimensional model of gasliquid two-phase flow with different nozzle angles and different nozzle diameters are established.The computational fluid dynamics software is used to simulate the gas liquid two phase flow field under different nozzle angles and different nozzle diameters which the influence of nozzle angle and nozzle diameter on spray lubrication can be got.Finally,the simulation is verified by experiments.The correctness of the simulation is verified by comparing the experimental data with the simulation data.The results show that the nozzle is more suitable for the small end surface;the nozzle is located in dimensionless radial 0.25 is more appropriate when the nozzle is spraying oil against down;the nozzle set in the dimensionless 0.8 is more appropriate when the nozzle is spraying oil against up.It is feasible to simplify the whole model to a single model;the nozzle angle and nozzle diameter have great influence on the entry of the injection fluid.When the nozzle is down and the nozzle angle is 30 degrees,the volume fraction of the oil injected into the bearing ring is the largest.When the nozzle is sprayed upwards,the volume fraction of oil in the bearing ring is the maximum when the nozzle angle is 30 degrees.Therefore,it is possible to improve the efficiency of oil injection by adjusting the nozzle angle and nozzle diameter;the method is verified by experiments.The experimental data are in good agreement with the simulation results,which verifies the accuracy and effectiveness of the simulation method.This paper obtained the motion characteristics of the gas phase and gas-liquid two-phase flow through the above,revealed the oil penetrativity on jet lubrication for transonic flow rolling bearings and some hindering factors.It is an important supplement to the formation of gas-liquid two-phase flow in bearing and providing a more in-depth theoretical basis in improving the lubrication effect of oil injection lubrication.