Coupled Analysis On Flow Field And Temperatrue Field Of High-speed Train Aluminum Gearbox

The gearbox is a key part of the transmission system in the high speed train.With the train speed increased sharply,the requirements for the comprehensive performance of gearbox has become increasingly strict.When the train runs fast,the speed and pressure of the oil in the gearbox change seriously.At the same time,the temperature of the power transmission system is also elevated,which has a bad influence on the lubrication and seal of the gearbox.As a result,it's necessary to analyze the flow field and the temperature field of the gearbox.The gearbox of high speed train is studied with hydrodynamic theory and heat transfer theory.A 2D simulation model of the flow field is established to investigate the oil-gas two-phase flow in the gearbox.The simulation is researched based on the VOF multiphase flow model and the RNG k-? turbulence model by using Multiple Rotating Reference Frames.The main contents and results are as follows:In the simulation,the lubricating oil is stirred by the gears and diffuse in the gearbox.The maximum speed appears in the engaging area.The lubricating oil around the bigger gear flows more slowly,while it eddies when it is close to the smaller one.The maximum pressure is positive which appears in the engageng-in area,and the minimum pressure is negative which appears in the engageng-out area.The flow field is investigated with different rotating speeds,immersion depths and viscosities.With higher speed,deeper immersion depth or smaller viscosity,the lubricating oil is easier to stir and the pressure changes earlier.Speed has a greater influence on pressure than depth and viscosity.The analysis of equilibrium temperature is also made.The reliability of simulation is identified through the experiment under maximum speed and full load.The simulation model is used to research the influences of speeds and depths on the pressure.It is showed that the engaging area has the highest temperature and the heat diffuses from the engaging area to the other areas.The temperature that is close to the wall of the gearbox is more uniform.After a balance time,the temperature distributes in a same way even though the gearbox is working on different conditions.The equilibrium temperature increases when the speed is higher or the oil is deeper.With the study on the simulations of flow field and temperature field,the distribution rules of lubricating oil,pressure,speed and temperature is investigated,which can optimize the lubrication,seal and heat dissipation of the gearbox.