基于环量分布的轴流双级风扇三维数值优化

将通流设计程序和叶片造型程序引入到遗传算法同响应面模型相结合的优化系统中,调用流场模拟软件,搭建了三维轴流压气机叶片的优化平台.该优化技术有四个特点:一是为与现代设计系统相接轨,不同于常见的用纯几何方法生成叶片,采用了传统的反问题设计方法生成三维叶片;二是不同于直接优化几何参数,优化自变量选取了设计中具有物理意义的气动参数;三是针对多级压气机的优化,提出了逐级优化策略;四是在优化过程中引入了直观分析法.算例选取了环量分布作为优化自变量,对某轴流双级风扇进行了以极大化非设计点流量为目标的优化;又对其改型设计进行了以极大化设计点绝热效率为目标的优化. 

Three-dimensional aerodynamic optimization for the two-stage axial-flow fan based on work distribution

By integrating genetic algorithm with response surface methodology,this paper developed an optimization system,with introduction of a quasi-three-dimensional through-flow design code and a blade formatting code.While a three-dimensional CFD (computational fluid dynamics) solver was involved,this paper established a numerical aerodynamic optimization platform for three-dimensional blades of axial-flow compressors.The optimization in this paper mainly has four features.First,it applies the conventional inverse design method instead of common CAGD (computer aided geometric design) parameterization method to generate a three-dimensional blade.Second,it chooses aerodynamic parameters with physical meaning as optimization design variables instead of purely geometrical parameters.Third,it presents a stage-by-stage optimization strategy about the multistage turbomachinery optimization.Fourth,it introduces the visual analysis method into optimization.The above techniques were applied,first,to a two-stage axial-flow fan for its maximum mass flow rate,and then,to the reformed two-stage axial-flow fan for its maximum adiabatic efficiency.The work distributions were taken as design variables,which were parametrically represented by means of Bézier curves.The two examples elucidate that not only the techniques mentioned above are appropriate and effective in engineering,but also the design guidance for similar inverse design problems can be obtained from the optimization results.