Simulation Of Jet Lubrication And Evaluation On Jet Effects For High-speed Gear Transmission

The high temperature of high-speed gears due to insufficient cooling of jet lubrication may cause pitting corrosion or scuffing failure.A temperature prediction method is proposed in this paper: By establishing a mathematical model of thermal elastohydrodynamic lubrication of gears considering the surface topography,and the instantaneous heat flux density of the tooth surface friction is deduced.The jet lubrication flow field is simulated by the LBM(Lattice Boltzman Method)-based CFD software XFlow,and the windage losses and convective heat transfer coefficient of the model under different parameters are analyzed.The above boundary conditions are input into the thermal module of the finite element solver software Ansys to solve the macroscopic temperature field,and the influence of different factors on the temperature field are obtained.A field test bench of temperature field of gears is built,and the test results are compared with the corresponding simulation results to verify the correctness of the simulation method.The main contents are listed as follows:(1)3D CFD simulations with different jet lubrication parameters are carried out in XFlow,the corresponding boundary inlet and outlet conditions are set.The experimental and simulated jet impingement processes are qualitatively compared to verify the reliability of the method and the best solution accuracy for the simulation is determined.Using the average oil-air ratio in the characteristic surface as a reference,the lubrication effects of different jet velocities,jet heights and jet angles are measured.(2)By establishing a mathematical model of gear thermal elastohydrodynamic unified lubrication considering the surface topography,the oil film thickness and the friction coefficient of the contact area is calculated,and then the instantaneous heat flux of the tooth surface friction is deduced as a basis for solving the boundary conditions of the temperature field.(3)Based on the CFD flow field,the windage losses and tooth-tosurface heat transfer coefficient during the operation process are solved,and a multi-field coupled finite element temperature simulation model is constructed to characterize the lubrication effects of the gears and analyze the influence of different factors on the temperature field.(4)The gear temperature field test scheme is determined,and the experimental results under different jet parameters are compared with the corresponding simulation results.The maximum relative error of temperature rise is 19.4%,which verifies the correctness of the simulation method.