Study On The Aerodynamic Noise Characteristics And Control Method Of The Pantograph For High-speed Trains

With the improvement of train speed,mechanical noise has relegated to a secondary position,while the aerodynamic noise gradually is dominant.Therefore,many scholars in the whole world have focused on the prediction and reduction of the aerodynamic noise of high-speed train.This paper investigates the high-speed train pantograph aerodynamic performance and noise using numeric methods.The research remarks are stressed as follows:(1)A 3D model of the front and rear chambers for a high-speed train is established to calculate numerically the flow field of sound pressure level spectrum diagram.The effectiveness of the 3D model established is verified by comparing the simulation results with that of the experiment.Measured results compared with the results of simulation error within 5%,prove that the simulation results are true and correct Simulation model.(2)A 3D model of pantograph for a high-speed train is established to analysis aerodynamic and force in the case of favorable state and adverse state by the numeric methods above,and get sound pressure level spectrum.The analysis results demonstrate that aerodynamic noise of pantograph increases with the increase of pressure.The pressure of pin joint between upper arm and lower arm is the maximum,and the pressure of lower arm is minimum.The total sound pressure level of the favorable state is bigger than adverse state.(3)Two kinds of the supporting arms of pantograph are proposed to reduce the aerodynamic noise.The first arm is variable cross section rod;the second is the wavy bar with the cross section formed by the sine wave rotating around the axis of the arm.At the cases of the inlet velocity of 83.3 m/s(300 km/h),the effects of the two kinds of arms on the drag reduction and noise reduction are analyzed.The analysis results demonstrate that the variable section arms are advantageous to enhance the aerodynamic performances and reduce noise in comparison with the cylindrical arms.When the arms of the pantograph are respectively nine kinds of wavy arms with three wavelength of 263,142 and 108 and three amplitudes of 0.5,1 and 2 mm,the aerodynamic noises are calculated and compared.The calculated results demonstrate that and the noise reduction effect of the wavy arms with 263 wavelength and amplitude of 2 mm is best,the noise reduction of which is 7.3dB.