Impacts Of Deflector Design On The Aerodynamic Performance Of The Pantograph On High-speed Train

With the increasing running speed of high-speed train,the pantograph located at the top of the train will be subjected to strong airflow excitation,which will increase the aerodynamic resistance,lift and aerodynamic noise of the pantograph,and seriously affect the energy saving and drag reduction of the train and the ride comfort.Installed the pantograph deflector is one of the effective methods to improve the aerodynamic performance of the pantograph,not only can change the flow field structure around the pantograph,reduce the aerodynamic drag and lift force of pantograph,also causes air currents to flow through the train at the top of the pantograph area,reduce the roof high and negative pressure zone formed by the airflow stagnation point range,improve the aerodynamic performance of the train.In this paper,the influence of different shape design of deflector on the aerodynamic performance of pantograph and its components under various working conditions is studied,which provides a reference for the shape design of pantograph deflector.Based on the aerodynamics of high-speed train,four different types of deflector shape schemes were constructed,and numerical simulation calculations were carried out for pantograph without deflector and under four deflectors at different speeds respectively.The influence of deflector shape design on pantograph aerodynamic performance was analyzed and discussed.Firstly,the surface pressure of the pantograph without the deflector and the pressure field and velocity field of the longitudinal profile were compared under different speed conditions.It was found that the area of high pressure on the pantograph and longitudinal profile would increase with the increase of train speed.Then,analyzed the flow field structure of pantograph and the surface pressure distribution under the different deflector shape schemes,and by comparing the four deflector shape under the scheme of pantograph aerodynamic drag and lift,found that the fully enclosed deflector can significantly change the lower area of the flow field structure of pantograph,eliminate the pantograph lower area of the maximum plus or minus pressure area,The aerodynamic resistance and lift of the pantograph are reduced to improve the aerodynamic performance of the pantograph.In order to further study the influence of different deflector shapes on the aerodynamic performance of pantograph,the six components of pantograph under four deflector shape schemes were simulated at different speeds respectively,in which the pantograph components were bow head,upper arm bar,lower arm bar,tie rod,bottom frame and insulator.By comparing four deflector shape under the scheme of the items constituting the pantograph aerodynamic drag and lift,the fully enclosed deflector improved the effect of pantograph upper arm lever and insulator components aerodynamic drag and lift is more apparent,the front and rear baffle and the side baffle of deflector with clearance can effectively reduce the lift force of lower arm bar and bottom frame components.The results show that the bow head contributes more to the aerodynamic resistance of the pantograph,and the upper arm contributes more to the aerodynamic lift of the pantograph.