Numerical Analysis And Optimization Design Of High Speed Gearbox Sealing System

The internal oil pressure fluctuation of gear reducer of High speed EMU is very large and the operating environment(train rendezvous,access tunnel,etc)is relatively poor.The external surface will generate a lot of negative pressure resulting in a large pressure difference inside and outside of the gearbox and finally the lubricating oil will leak outside of gear reducer under the role of pressure difference.This not only wastes energy,but also safe driving of high-speed EMU can't be guaranteed.Therefore,the leakage problem of labyrinth seal system is urgently needed to be solved.At present,the CFD technology is widely applied to the numerical calculation of labyrinth seal system and it has the advantages of lower cost,shorter research and design cycle and lower workload,etc.Therefore,this paper carries out numerical analysis of internal flow field of the labyrinth seal system by using the Fluent analysis software and optimizes the design of labyrinth seal system.Firstly,Setting labyrinth seal system of the gear reducer of High speed EMU as the original model and drawing the labyrinth seal calculation model at the input and the output shaft end of the gear box and respectively making numerical analysis of the input and output shaft of labyrinth seal system by changing the sealing gap.Among them,the minimum backlash of output shaft seal system decreases by 71.66% compared with the leakage of maximum backlash.The minimum backlash of input shaft seal system decreases by 88.07% compared with the leakage of maximum backlash.The results show that the leakage decreases with the decrease of the seal backlash;Secondly,this paper analyzes the impact of axial labyrinth seal's number of cavity,cavity width,cavity depth and tooth width on the sealing efficiency of labyrinth seal system by making numerical analysis on through-type axial labyrinth seal system and setting the part of the axial labyrinth seal system of original model as calculation basis.According to the analysis results,the cavity size of the axial labyrinth seal system is optimized to obtain a through-type axial labyrinth seal system with reasonable cavity size;Finally,applying the optimized axial labyrinth seal system to the whole sealing structure and carrying out the numerical simulation of the optimized whole sealing structure,the optimized whole sealing structure is compared before optimization.Among them,the leakage of the input shaft labyrinth seal system reduces by 30.5% after optimization,and the leakage of the output shaft labyrinth seal system reduces by 27.8%,which verifies the feasibility of the optimized whole labyrinth seal system and provides technical support for the design of labyrinth seal system of train gear box.