高速磁浮列车头型多目标气动优化设计

针对常温常导高速磁浮列车头型的几何特点,将其分为流线型和设备舱2个部分,采用改进的VMF参数化方法和曲面离散方法,分别进行参数化设计;对提取的12个设计参数,结合计算流体力学方法、支持向量机模型和多目标粒子群算法,以整车气动阻力系数和尾车气动升力系数为优化目标,以头车气动升力系数为约束条件,进行高速磁浮列车头型多目标气动优化设计,并进行设计参数的灵敏度分析;对优化外形进行工程化改进和风洞试验验证。结果表明:参数化设计方法能够利用较少的设计参数描述高速磁浮列车头型;减少计算量且提高优化效率的支持向量机模型的预测精度满足设计要求;头型长度是影响高速磁浮列车气动性能的关键设计参数,水平剖面型线对头尾车气动升力的影响较为显著;较原始外形,采用根据工程设计要求改进的优化外形后,整车气动阻力系数减小19.2%,头车和尾车气动升力系数分别减小24.8%和51.3%。

Multi-Objective Aerodynamic Optimization Design of High-Speed Maglev Train Nose

The nose of normal temperature and normal conduction high-speed maglev train is divided into streamlined part and equipment cabin according to its geometric characteristics.Then the modified VMF parameterization method and surface discretization method are adopted for the parametric design of the nose.For the 12 key design parameters extracted,combined with computational fluid dynamics,support vector machine model and multi-objective particle swarm optimization algorithm,the multi-objective aerodynamic optimization design of high-speed maglev train nose and the sensitivity analysis of design parameters are carried out with aerodynamic drag coefficient of the whole vehicle and the aerodynamic lift coefficient of the trailing car as the optimization objectives and the aerodynamic lift coefficient of the leading car as the constraint.The engineering improvement and wind tunnel test verification of the optimized shape are done.Results show that the parametric design method can use less design parameters to describe the nose shape of high-speed maglev train.The prediction accuracy of the support vector machine model with the reduced amount of calculation and improved optimization efficiency meets the design requirements.The nose length is the key design parameter affecting the aerodynamic performance of high-speed maglev train,and the horizontal profile has a significant impact on the aerodynamic lift of the leading and trailing cars.Compared with the original shape,the aerodynamic drag coefficient of the whole vehicle is reduced by 19.2%,and the aerodynamic lift coefficients of the leading and trailing cars are reduced by 24.8%and 51.3%respectively after adopting the optimized shape modified according to engineering design requirements.