Optimization Design And Aerodynamic Chacteristics Analysis On Pantograph Diversion Device Of High-speed Trains

It is an inevitable trend of railway development in the world to improve the running speed of passenger trains.When the running speed of the train increases,there will be some aerodynamic problems,such as reducing passenger comfort,increasing the running energy consumption of the train and affecting the safety of the train.Pantograph is an important part of high-speed train,which has an important impact on the aerodynamic performance of the train.Setting a pantograph guide device in the pantograph area can not only improve the air flow state of the pantograph area,reduce the aerodynamic resistance of the pantograph,but also improve the air aerodynamic performance of the train.Therefore,it is of great practical significance to optimize the design of pantograph guide device.Based on the theory of train aerodynamic characteristics and numerical simulation,this paper uses CFD method to simulate the high-speed train models with different pantograph guide devices.Using ANSYS fluent 19.0 fluid calculation software,the numerical value of three types of high-speed train models at different speeds is calculated successively.According to the obtained velocity streamline diagram and surface pressure distribution cloud diagram of pantograph guide device,as well as the aerodynamic resistance data of pantograph head,middle part,lower part,guide cover and train body,the specific influence of different pantograph guide devices on the aerodynamic characteristics of pantograph and train body at different speeds is studied,and the comprehensive improvement of pantograph and train is obtained The pantograph guide device with the best aerodynamic characteristics of the whole vehicle.The results show that:(1)Among the three kinds of pantograph fairings,the double arch surface fairing has the most significant effect on improving the flow field structure of the lower part of the pantograph;the ellipsoid surface fairing has the best surface pressure distribution;the double arch surface fairing has the best effect on reducing the resistance of the pantograph,which is 17.7% and 10.4% lower than the ellipsoid and the guide surface fairing;in the aerodynamic resistance of the pantograph system,the aerodynamic resistance of the pantograph fairing Compared with the aerodynamic resistance of the pantograph,the aerodynamic resistance of the ellipsoid,the double arch surface and the guide surface of the pantograph fairing respectively accounts for 53.3%,80.1% and 63.6% of the aerodynamic resistance of the pantograph system;in terms of reducing the aerodynamic resistance of the whole train,the ellipsoid fairing is the best,which is 26.5% and 4.0% lower than the double arch surface and the guide surface fairing respectively.In a comprehensive consideration,the ellipsoid pantograph fairing has the best effect on improving the aerodynamic characteristics of the train.(2)Among the four kinds of pantograph guide cabins,the rectangular guide cabins have the most significant effect on improving the flow field structure of the lower part of the pantograph;the surface pressure distribution of the rectangular guide cabins is the best;in improving the aerodynamic resistance of the pantograph,the rectangular guide cabins have the best effect on improving the aerodynamic resistance of the pantograph.Compared with the elliptical,capsule and hexagon guide cabins,the drag reduction rate has increased by 3.4% 3.5%,2.9%;in terms of improving the aerodynamic resistance of the whole train,the rectangular guide tank has the best effect on improving the aerodynamic resistance of the whole train.Compared with the elliptical,capsule and hexagon guide tanks,the drag reduction rate has increased by 1.2%,0.7% and 1.1% respectively.Comprehensive consideration,the rectangular pantograph diversion cabin has the best effect on improving the aerodynamic characteristics of the train.(3)Among the different pantograph guide devices,the rectangular guide cabin has the best drag reduction effect on the pantograph and the whole train.Compared with the scheme without pantograph guide device,the rectangular guide cabin reduces 37.0% of the aerodynamic resistance of pantograph,and the rectangular guide cabin reduces 7.5% of the aerodynamic resistance of pantograph compared with the scheme with ellipsoidal guide hood.Compared with the ellipsoid fairing scheme,the rectangular fairing reduces the aerodynamic drag by 5.2%.To sum up,the rectangular pantograph guide cabin is the best one among the seven pantograph guide devices.The research results can provide a theoretical basis for reducing aerodynamic resistance and energy saving of high-speed train.