基于FFD方法的离心压气机叶片优化设计与试验

为了改善离心压气机叶片多工况优化设计时面临的设计空间大、冗余搜索、灵活性不足、优化效率低等问题,提出了基于自由曲面变形技术(free form deform, FFD)的离心压气机复杂曲面叶片参数化方法,建立了叶片局部几何区域与三维空间网格控制体的映射模型,研究了样条曲线基函数几何特性对叶片几何构型的影响,实现了离心压气机叶片几何外形的局部精细化改型.结合B样条基FFD参数化方法、多目标进化算法和计算流体动力学对复杂叶片的局部区域进行了多工况气动寻优,优化结果表明:在满足约束条件的情况下,流场结构得到进一步的改善,额定工况和常用工况等熵效率分别提高了0.48%和0.40%,喘振裕度分别提升了1.6%和1.8%,利用较少的设计变量实现了离心压气机复杂曲面叶片高效灵活的精细化设计,为离心叶轮的气动优化设计提供了新的理论依据.

Optimal design and experiment of centrifugal compressor blades based on FFD method

The optimal design of centrifugal compressor blade with multiple working conditions faces the problems of large design space and insufficient flexibility, thus causing redundant blind search and reducing the optimization efficiency. In order to improve the above problems, the FFD-based parameterization method of centrifugal compressor blade with complex surface was proposed, for which a mapping model of local geometric region and mesh control body was established, the influence law of diffe-rent basis functions on blade geometry configuration was explored, and the fine optimization of blade geometry shape was carried out by combining multi-objective evolutionary algorithm and CFD technology. The results show that the optimized flow field structure is further improved, the isentropic efficiency of rated and common conditions is increased by 0.48 % and 0.40 %, respectively, and their surge margins are as well increased by 1.6 % and 1.8 %, respectively, which achieves an efficient and flexible fine design of centrifugal compressor blade with complex curved surface by using less design variables.