Research On Aerodynamic Characteristics And Operation Safety Of High-speed Trains In Strong Sandstorm Environment

With the fast growth progress of contemporary society and the continuous upgrading of high-speed railway,it is attracting increasingly attention to the aerodynamic performance of trains.There are many Wasteland and the Gobi Desert in the northwest of China,and the sandstorm covers a large area in the region,it is easy to cause sand disaster,it is always threatening the safety of the high-speed trains.So,it is necessary to research the aerodynamic characteristics and operation safety of high-speed train under strong wind and sand environment.In this paper,multiphase flow calculation is carried out in sand environment and wind sand environment.Based on Euler-Lagrange method,aerodynamics models of high-speed trains in sand environment and wind sand environment are established respectively,and the accuracy of the models is verified.The aerodynamic characteristics of the high-speed train in sand and wind environment are analyzed.The multi-body system dynamics model of the train is established to study the influence of strong wind and sand environment on the safety of high-speed train operation.The erosion model of high-speed train was established to study the effect of sand particles on the erosion effect of high-speed train at different speeds and wind speeds.The results show that:the aerodynamic resistance of the train increases with the increase of the speed and sand concentration compared with the sand-free condition.When the speed is 350km/h and the sand concentration is 0.05kg/m~3,the aerodynamic resistance of the first train increases by 4%and the aerodynamic resistance of the tail train increases by 6.6%.The aerodynamic force and aerodynamic moment of the train increase with the increase of the speed and wind speed in the sandstorm environment.When the speed is300km/h?the wind speed is 30m/s?and the sand concentration is 0.05kg/m~3,the aerodynamic lift,aerodynamic side force,aerodynamic side rolling moment,aerodynamic nods moment and aerodynamic nods moment of the train are relative to those of the sand-free condition.With the increase of 11%?15.9%?4.2%?4.5%and 1.7%,the aerodynamic load coefficient of the first vehicle can be approximately fitted to the relation of sand concentration?combined wind speed and slip angle.The safety index of train operation becomes worse with the increase of sand concentration.The operating safety range of high-speed train in sand environment is smaller than that of high-speed train in pure cross wind environment.The impact of sand particles will cause serious erosion effect on the train,and the erosion effect increases with the increase of sand particle concentration,speed and wind speed,and the sand particle erosion effect on the first train is the most significant.