Research On Anti-snow Performance Of High-speed EMU Bogie Areas

High-speed EMU in alpine snow running environment,train air carrying snow grains rapid movement will inevitably through the bogie surface of equipment,the equipment surface temperature is higher in snow grains quickly heated to melt,more snow grains landing on the equipment surface adhesion with the snow melt,the process cycle continuously,cause bogie area gradually snow,eventually form severe icing phenomenon.This will cause performance decline,life shortening and damage of bogie parts,which will bring many difficulties to the late safe operation and maintenance of High-speed EMU,and affect the comfort and safety of train operation and passenger travel.In this dissertation,based on the three-dimensional unsteady incompressible N-S equation,RNG turbulence model and discrete phase model,the computational fluid dynamics software Fluent was used to simulate the flow field structure and the movement characteristics of snow particles in the bogie area of EMU.The main research contents of this dissertation are as follows :(1)According to the actual size,the 3D model of the three-time EMU is created,and the structure of the bogie area is drawn in detail,in which the important structures of the motor car and the trailer bogie are retained;According to the requirements of simulation calculation,the flow field calculation field of EMU was established,and the physical parameters of snow and snow phases were set up.ICEM software was used to divide the grid,and local encryption of key positions was carried out.The boundary conditions such as inlet wind speed,snow particle parameters and adhesion conditions were determined.(2)The flow field distribution and the adhesion state of snow particles around the bogie of high-speed EMU were simulated and calculated.The pressure distribution,flow line at the center plane,snow concentration distribution and the number of adhesion particles in the bogie area of the first car,middle car and rear car were analyzed.(3)Two optimization schemes of guide plates were put forward,namely,the front of the bogie with a front tetrahedral guide plate and the middle of the bogie with a middle guide plate.The same calculation method as the original model was adopted to compare and analyze the influence of the front and middle guide plates on the flow field characteristics and snow particle adhesion of the EMU bogie under different working conditions and parameters.The results show that :(1)The flow field characteristics in the bogie area are similar to the flow characteristics of snow particles,and the adhesion number of snow particles on each part is closely related to the flow field disturbance around it;(2)When the height of the front guide plate is set to 40 mm,60mm and 80 mm,the snowflake adhesion number of the corresponding bogie decreases by 12.36%,38.22% and 62.13%,respectively,compared with the original one.Therefore,it can be seen that the 80 mm front guide plate has a more obvious advantage in snow prevention performance.(3)When the middle guide plate is 220 cm in length,30 cm in width,10 mm in thickness and 30°,45°and 60°in inclination,the adhesion of snow particles decreases by 15.78%,28.26% and 27.78%,respectively,it is found that the middle guide plates of 45°and60°have better snow protection performance in the bogie of EMU,but the middle guide plates of 45°have better protection effect on the bogie of EMU.The research results in this dissertation are of high practical value and can provide theoretical support for preventing snow and ice in bogie area of high-speed EMU.