Aerodynamic Characteristics And Flow Field Analysis Of High Speed Train Under Strong Cross Wind Environment

In recent years,China’s railway development is very rapid,is a vast country,the high speed train through the advantages and disadvantages of the environment is obviously different.Especially in the west of China,the environment is relatively bad.The strong sand carrying wind not only has a great impact on the aerodynamics of high-speed trains,but also has different impact on the surface of high-speed trains.Therefore,the safety of high-speed trains is difficult to guarantee.In order to study the influence of cross wind,speed,sand and embankment on the aerodynamic performance of high-speed trains in the western environment conditions,In this paper,Based on the aerodynamics theory,the Navier Stokes equation and the standard k-e turbulence model were used to continuously process the airflow;the DPM model is used to discretize the sand particles,and the fluid software is used to simulate the aerodynamic performance and erosion of high-speed train.(1)The aerodynamic performance of high-speed train on flat ground is simulated numerically by using simplified model and ignoring the parts such as receiver and windshield.The simulated speed of the train is 200km/h,and the pressure,lift and resistance of the train under different sand particle diameters are analyzed.The erosion rate of sand particles on the surface of high-speed train increases with the increase of wind speed;the erosion rate increases with the increase of sand particle diameter.When the sand particle diameter is 1 mm,the change rate of erosion rate is greatly affected by wind speed,and the change rate is small under other sand particle diameters.This study provides a reference for the protection of train surface in the sandstorm environment.(2)When the train is running on a single-track embankment,the isobars at the head of the train are relatively dense and the maximum pressure appears on the side of the nose wing,while the isopressure line of the tail car is sparse;When driving in the sand carrying wind environment,the positive pressure value under the inclination of each embankment decreases.When the wind speed increases,the maximum positive pressure area of the train increases,but when the train runs in the sand-carrying wind environment,the pressure is relatively reduced.When the train runs along the single-track embankment,the double-track embankment and the half-cut embankment,a vortex is formed on the leeward side of the train and its size increases with the increase of the embankment inclination,but the vortex range is different under each working condition,and at the center of the vortex,the pressure changes are quite dramatic.(3)The aerodynamic performance of high-speed train on single-track embankment,double-track embankment and half-cut embankment is numerically simulated,the relationships between the lateral force,lift force,lateral force coefficient,lift force coefficient and overturning moment coefficient of the train and the embankment inclination,wind speed and vehicle speed are calculated,The change of side force,lift force,side force coefficient,lift coefficient and overturning moment coefficient of the train under the condition of sand carrying wind are compared.Therefore,a new understanding of the aerodynamic performance of the train in sand-laden wind environment is obtained,which provides a reference for the safe operation of the train in the Western environment and for the selection of the embankment inclination.