Abstract:

Reducing the running resistance and aerodynamic noise is the effective way to improve the operational speed and environment adaptability of high-speed EMU. Aiming at two targets including aerodynamic resistance and noise, an aerodynamic performance optimization design process for a new EMU head-type is established with Isight software, the steps of which including parameteric-driven modeling, mesh generation, aerodynamic calculation and optimization analysis automatically. Based on multi-objective genetic algorithm NSGA-II, a multi-objective integrated optimization design is completed for 3 key design variables including nose tip height, expansion amount of control points on the cowcatcher and inclination angle of bogie region baffle. Meanwhile, a correlation analysis is performed on aerodynamic resistance and aerodynamic noise with the 3 key design variables. Then the better aerodynamic shapes of the head were put forward. It can be seen through the calculation result that: ① the correlation of nose tip height of the head car with both resistance and maximum surface sound power level are positive; ② the influence of inclination angle of bogie region baffle on the resistance and maximum surface sound power of the head car is the most significant; ③ the maximum surface sound power level can be obviously reduced by optimizing the inclination angle of bogie region baffle.

Key words: high speed EMU, multi-objective optimization, noise, resistance