Research On The Interior Noise Prediction Of High Speed Train And Its Control

With speed increasing of the high-speed train,the research on the car interior noise have been became more and more important.In this paper,the inner noises of CRH3 EMU are taken as a researching object,the statistical energy analysis model including a head car and an intermediate car is established,the aerodynamic noise source is calculated,and basing on the basic principle of the statistical energy,the car interior noises are simulated and analyzed using the VA One software.The main research contents are as follows:(1)The statistical energy models of floor,side wall,windows and roof structure for CRH3 EMU carbody are established,the every model include the aluminum alloy structure,porous insulation material and interior plate which have a significant effect on the noise transmission as a key component,then the sound insulation performance are calculated basing on the statistical energy method?(2)The statistical energy model of EMU car is established for acoustic simuation.The carbody structure making by aluminum extrusions are equivalent to uniform sheet which the acoustic insulation losses are same with the original aluminum extrusions.Basing on this acoustic equivalent,the statistical energy model including a head car and an intermediate car is established,it include 929 structure systems for carbody and 2056 acoustic cavity system for car inside and outside local sound field.(3)The aerodynamic noises of the high-speed train with a head car,intermediate car and a rear car are calculated using Fluent software at the speeds of 200km/h,250km/h and 300km/h,the pantograph and bogies are considered in model.Firstly,the steady flow states of the high speed train are computed,and the steady results are used as the initial values,then the transient flow states of the high speed train are computed using the large eddy simulation,while the aerodynamic noises are calculated near the carbody surface area.(4)The aerodynamic noises of high-speed train and wheel rail noises are used as the excitation noise source,the aerodynamic noises are loaded on the corresponding parts of high-speed train acoustic analysis model respectively,the wheel rail noises are applied on the bogie area,then the carbody interior noises are simulated and analyzed basing on the statistical energy analysis method at the speed of 200km/h,250km/h and 300km/h,and the effects of porous sound-absorbing material thickness on the car interior noises are analyzed.(5)The testes of the car interior noises for CRH3 high-speed train are accomplished using a portable noise tester,the noise spectrums are achieved at under different operating speeds,and tested results are compared with the simulated results.The results show that the noises inside the carbody are increasing with the train speed increasing,the car interior noises are decreased with the frequencies increasing at certain speeds,the aerodynamic noises have a larger contribution to car interior noises in middle and lower frequencies,and the noises at the bogie fields have a larger contribution to the car interior noised in high frequency.Along the longitudinal direction of the car,the noise at the driver cabin of head car and at the pantograph field of middle car are larger than other fields,the noises of the windshield are more prominent,and the noises in the center of car are relatively smaller.The validity of the simulation results has been verified by a comparing analysis with the test results.