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建立了一套基于计算流体力学(CFD)/FW-H_pds方程(Ffowcs Williams-Hawkings equations with penetrable data surface)的气动噪声预估技术和组合优化算法的低噪声旋翼桨尖平面外形设计方法。首先,采用积分形式的可压雷诺平均Navier-Stokes(RANS)方程作为旋翼流场求解控制方程,围绕旋翼流场的网格采用嵌套网格方法生成。在优化过程中,桨叶网格生成采用提出的高效参数化的网格自动生成方法。在建立的CFD方法求解基础上,采用基于可穿透旋转积分面的鲁棒性较好的FW-H_pds方程来求解旋翼高速脉冲(HSI)噪声。然后,以降低旋翼HSI噪声为目标,以旋翼悬停气动性能为约束,提出具备前掠-后掠-尖削等组合特征的桨尖外形方案并进行优化分析。将基于拉丁超立方(LHS)方法和径向基函数(RBF)的代理模型方法耦合到遗传算法过程中,建立了一种高效的组合优化算法。在当前的计算状态下,优化后的桨尖外形的负压峰值相比于矩形桨叶降低了58.4%,优化后的桨叶有效地减弱了旋翼桨尖区域的跨声速“离域化”现象,因此可以降低旋翼HSI噪声特性,同时可以减弱旋翼桨尖涡强度达30%,旋翼悬停性能提高了2%~3%。
A set of low-noise rotor blade tip plane profile design methods based on CFD / FW-H_pds equation and aerodynamic noise estimation and combinatorial optimization algorithm are established. First, the integral Navier-Stokes (RANS) equation is used to solve the governing equations of rotor flow field. The mesh around the rotor flow field is generated by nested grid method. In the process of optimization, the grid generation of the paddle adopts the proposed automatic parametric grid generation method. Based on the established CFD method, the rotor robust high speed FW-H_pds equation is used to solve rotor high-speed impulse (HSI) noise. Then, to reduce the HSI noise of the rotor aiming at the constraint of aerodynamic performance of the rotor hovering, a tip profile scheme with combination features of forward swept-back swept-taper is proposed and optimized. The method of proxy model based on Latin hypercube (LHS) and radial basis function (RBF) is coupled to the genetic algorithm, and an efficient combinatorial optimization algorithm is established. In the current state of calculation, the peak value of the negative pressure of the optimized tip shape is reduced by 58.4% compared with that of the rectangular blade, and the optimized blade effectively reduces the transonic speed of the tip region of the rotor "Phenomenon, so it can reduce the rotor HSI noise characteristics, while reducing the rotor blade tip vortex intensity of 30%, rotor hover performance increased by 2% to 3%.