旋翼翼型高维多目标气动优化设计

Many-objective aerodynamic optimization design for rotor airfoils

先进旋翼翼型设计是典型的多设计点、多目标优化问题,常规优化方法已无法满足翼型高维多目标优化设计的要求。基于分解的多目标优化算法(MOEA/D),建立了考虑高低速升阻特性、力矩特性、阻力发散特性等的旋翼翼型高维多目标优化设计方法,并采用高精度kriging模型以提高优化设计效率。针对旋翼内段、中段翼型进行了5个设计目标的全局优化设计,采用自组织图映射(SOM)方法对最优Pareto解集进行了聚类分析。典型翼型CFD结果分析表明,中段翼型低速力矩系数幅值减小约50.7%,高速最大升力系数提高约6.5%,最大升阻比提高约7.7%,同时阻力发散特性得到改善,内段翼型同样取得了良好的多目标优化效果。研究表明,MOEA/D算法对高维多目标气动优化设计问题具有很好的适应性,能有效提升旋翼高低速气动性能设计的能力。

The design of advanced rotor airfoils is a typical multi-design-condition and multi-objective optimization problem, and traditional optimization methods cannot meet the requirement of high-dimensional multi-objective optimization design for airfoils. In this paper, a many-objective optimization design method for rotor airfoils is proposed based on the multi-objective evolutionary algorithm based on decomposition(MOEA/D), which considers the lift and drag performance under both low-and high-speed conditions, moment performance and drag divergence performance. The high-precision kriging model is utilized to improve the optimization design efficiency. Five-objective global optimization design for the inner section and middle section of the rotor airfoil is conducted in this paper. The optimal Pareto solution set is clustering analyzed by the self-organizing mapping(SOM) and a representative rotor airfoil is selected and analyzed using the CFD solver. The results show that, for the airfoil in the middle section, the magnitude of the moment coefficient at low speed is reduced by about 50.7%. At high speed, the maximum lift coefficient is improved by about 6.5%, and the maximum lift-to-drag ratio is increased by about 7.7%, and meanwhile the drag divergence performance is enhanced. Evident performance improvement for the inner section airfoil is also achieved. The results show that the MODA/D is suitable for many-objective aerodynamic optimization design problems, and the proposed method can effectively improve the low-and high-speed aerodynamic performance design capability for the rotor airfoil.