Study On Erosion Wear And Insulation Characteristics Of EMU Roof Insulators Under Wind Sand Environment

Lanzhou-Xinjiang High Speed Railway is China's first high-speed railway which goes through alpine regions,plateau regions,and Gobi regions and has important strategic significance,there are five strong wind areas along the line across the region,sand in the strong wind has very large relative speed to trains,the insulator surface roughness increases or even appears micro cracks because of the high speed,which may lead to the decrease of insulating property or short operation life of insulator and other serious consequences.Study on erosion and insulation characteristics of EMU(Electric Multiple Units)roof insulator uder sandy environment has important engineering value and significance for safe and stable operation of Lanzhou-Xinjiang High Speed Railway.The erosion wear of different parts of the vehicle roof post insulators is first studied in this paper,and the numerical simulation of the erosion wear of the insulator is realized by using the K-epsilon RNG turbulence model and discrete phase model.The simulation results show that the wear rate of insulator changes in M shape distribution with the edge position,the maximum wear position is near 45 degrees;the simulation results and the experimental results are in good agreement,which can provide the basis for the structure optimization and operation life prediction of insulator uder sandy environment.The erosion wear rate of each part of the umbrella skirts increase with the increase of the air velocity and the particle size of the sand particles,and the maximum erosion rate position move outwards.In order to further analyze the influence on the performance of insulators of erosion wear,insulator erosion test of different hours is conducted in closed wind tunnel,insulator surface micro-topography was observed using optical microscopy after different hours of erosion test,the insulator surface roughness increases with erosion time under 160 h.The hydrophobicity properties of the insulator surfaces was detected after hours of erosion test,hydrophobicity properties degree decreased with the increase of erosion time;insulator AC pollution flashover test was conducted after erosion test,the experimental results show that the erosion time has little effect on the growth of flashover voltage,but it has a great effect on the flashover channel.