Research On Drag Reduction Of Smoothing Design In The Sinking Platform Area Of High-speed Train Pantograph

In the thesis,the numerical simulation method is utilized to study the smoothing design at the bottom of the pantograph of high-speed train,aiming for drag reduction.A simplified model for the simulation of pantograph area is proposed.On this basis,the smoothing structure at the bottom of the pantograph area and critical shape parameters are studied.The influence of smoothing design on time-averaging and dynamic force of pantograph and car body is analyzed.Finally,a smoothing covering scheme with drag reduction optimization is obtained.(1)A reliable simplified model for simulating pantograph area of high-speed train is established.The influence of the height,length,bogie and insulator of the train model on the grid strategy and drag prediction are revealed.(2)The smooth design idea and covering structure at the bottom of pantograph for drag reduction are proposed.For two kinds of smoothing design ideas: flattened covering and convex covering,the IDDES method is used to analyz the difference of aerodynamic characteristics in the pantograph area.The correlation between the drag reduction rate of the roof model and the covering rate,the convex height and the height of the sinking platform is obtained.The smoothed structure with the highest drag reduction rate for two types of design schemes are confirmed:(1)The flattened covering structure with the best comprehensive performance,with the coating rate of 68.19% and drag reduction rate of 15.26%;(2)The convex covering structure with the best drag reduction effect,with the convex height of 283 mm and drag reduction rate of 16.94%;(3)The convex covering structure affects the lifting force of panhead,while the flattened covering structure has little effect.(3)The drag reduction effect of the flattened covering structure on the three car train model is verified.The overall drag reduction rates of raised pantograph and folded pantograph models are 4.01% and 5.30%respectively.In conclusion,the smoothing covering structure proposed in this paper is effective and feasible,and the engineering application of the research results is promising.