Simulation Analysis On Fluid And Temperature Field Of Bevel Gears Based On Heat-Fluid Coupling

With high transmission efficiency and high flexibility, gear has been widely applied tothe fields of engineering machine, automobile, aerospace, etc. However, in the process ofgear transmission, a lot of heat would be generated as the relative sliding friction betweentooth surfaces. If the generated heat can’t be dissipated quickly, it would lead to gearboxtemperature rising sharply, which can cause the gear scuffing failure and pitting failure. Inthe meantime, It would also change the physical parameters of the lubrication, and thusreduce the lubricating property. The factors, such as flow characteristic of lubrication, thegeometric parameters and load of gears, have the most significant effects on temperaturefield of gears. The research of fluid and temperature field is very meaningful for design oflubrication system and gears.In this paper, partial content is supported by the national natural science foundationproject-"Design Theory and Method for Power Split Device（PSD）of Hybrid ElectricVehicle in Multi-field Coupling (51075179)". This paper study the fluid and temperaturefield of bevel gears based on Heat-Fluid Coupled, form the simulation analysis methodused to study the fluid，convective heat transfer and temperature field of gears. The maincontents include the following points:(1) The computational fluid dynamics method was analyzed, and the simulationmodels of heat-fluid coupled for gears transmission is established through simplifying themodel of PSD, meshing and setting boundary conditions.(2) The simulation method of flow and heat transfer was analyzed from dynamic meshmodel, convergence criteria and heat-fluid coupled analysis process. The pressure of fluidunder different lubricant viscosity and the fluid velocity under different rotational speed ofgear were analyzed using the Fluent software based on the established simulation models.The results show that the pressure of fluid increases as the lubricant viscosity increases,fluid velocity also increases as the gear rotational speed increases, and the maximum offluid pressure and velocity are both at gear teeth meshing point. (3) The transfer path and balance process of heat in PSD were analyzed. Theproduction and distribution of friction heat were determined through solving the toothsurface relative sliding speed, tooth surface contact stress, sliding friction coefficient andother parameters in the process of gear meshing. Combining the heat transfer models withfluid-flow model, the convection heat transfer coefficients of the tooth surface was obtainedthrough the simulation analyses of heat-fluid coupling, and the results were compared withthe empirical value. The results show that the simulation results obtained by heat-fluidcoupling can better reflect the distribution of convective heat transfer coefficient. Thispaper provide a means to solve the convective heat transfer coefficient of gear toothsurface.(4) The analyze methods and influence factors of gear temperature field weresummarized. The finite element models were established using Abaqus software accordingto the convective heat transfer coefficient that had already been obtained. The influence ofthe tooth width, modulus, modification coefficient and load on the gear temperature fieldwere analyzed based on the finite element models. The results show that the change ofgeometry parameters especially tooth width and load of gear have great influence on geartemperature field.(5) At last, the paper gived a summary of the full text, and pointed out thedeficiencies.