Aerodynamic Simulation And Structural Optimization Of High-speed Train

With the increase of the speed of high-speed train,the aerodynamic problems of high-speed train are becoming more and more significant.The aerodynamic parameters of high-speed train,such as the aerodynamic drag,aerodynamic lift,air noise and aerodynamic transverse force,are closely related to the geometric surface of head shape,so the optimization design of train head shape is the main measure to improve the noise performance and aerodynamic performance of train.Aerodynamic simulation and structural optimization of high-speed train were studied in this paper,which has important engineering significance.The aerodynamic simulation of high-speed train running in open air or under the cross wind condition was carried out.The model of three high-speed train assembly was established,and Hyper Mesh software was used to establish computing domain and mesh division.Fluent software was used to calculate and analyze the pressure distribution of high-speed train surface and sound power of train surface noise source of high-speed train,and the direction for the optimization of train shape was pointed out.To further improve the aerodynamic and noise performance of high-speed train running in open air and reduce the aerodynamic drag,aerodynamic lift and sound power of the train surface noise source,the multi-objective optimization design of high-speed train head shape was implemented.Seven groups of optimization design variables were selected in three directions of the train(vertical,horizontal and vertical),the Optimal Latin Hypercube design was used to sample,and the arbitrary shape deformation(ASD)technique was used to obtain the sample quickly.Based on the three-dimensional incompressible governing equations and k-ε turbulence model,the train was simulated.The response surface function approximation model of design variables was constructed with respect to the aerodynamic drag,lift and sound power of the train surface noise source.Through the genetic algorithm NSGA-II to optimize the streamline shape of train,a series of Pareto optimal head shapes were gained,a more comprehensive train head shape was chosen.Compared with original train,aerodynamic drag of the optimized train was reduced by 5.21%,aerodynamic lift was reduced by 36.68%,and the sound power of the train surface noise source was reduced by 2.11%,the aerodynamic and noise performance of the high-speed train were improved.To further improve the aerodynamic performance of high-speed train running under the cross winds,and reduce the aerodynamic drag,aerodynamic lift and aerodynamic transverse force,the multi-objective optimization design of high-speed train head shape was implemented.Six groups of optimization design variables were selected in three directions of the train,the Optimal Latin Hypercube design was used to sample,and the arbitrary shape deformation technique was used to obtain the sample,and the train was simulated.The radial basis function network approximation model of variables was constructed with respect to aerodynamic drag,lift and transverse force.Through the genetic algorithm NSGA-II to optimize the streamline shape of high-speed train,a series of Pareto optimal head shapes were gained,a more comprehensive train head shape was chosen.Compared with original train,aerodynamic drag of the optimized train was reduced by 3.84%,aerodynamic lift was reduced by 3.25%,and the aerodynamic transverse force was reduced by 3.54%,the aerodynamic performance of the high-speed train was improved.