高速列车头型气动外形关键结构参数优化设计*

降低列车运行阻力和气动噪声是提升高速列车速度能力和环境适应性的有效手段。针对气动阻力、气动噪声这两项优化目标，利用Isight软件建立了集参数化驱动建模、计算网格划分、气动计算、优化分析等步骤的高速列车新头型气动性能自动优化设计流程，运用基于多目标遗传算法NSGA-II的优化设计方法，对鼻尖高度、排障器前端伸缩量、转向架区域挡板倾角等关键设计变量进行了优化设计以及与气动阻力和气动噪声的相关性分析，在此基础上提出了综合性能较佳的新头型气动外形。通过计算结果可知，① 鼻尖高度对整车阻力和头车表面最大声功率均为正相关关系;② 转向架区域隔墙倾角对整车阻力和头车表面最大声功率影响的相关性最大;③ 通过优化转向架区域隔墙倾角可有效降低该处气动噪声的表面声功率。

Optimization Design on Key Structural Parameter of High Speed EMU Head-type Aerodynamic Shape

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.