飞机螺旋桨低噪声多学科优化设计与试验验证研究

Multi-Disciplinary Design and Experimental Verification of Low Noise Aircraft Propellers

关键词:  螺旋桨  气动  气动噪声  多学科  设计  试验

Key words:  Propeller  Aerodynamic  Aeroacoustics  Multidisciplinary  Design  Experiment

摘要:

为进一步降低飞机螺旋桨气动噪声，针对飞机螺旋桨开展综合考虑气动、噪声和结构强度的低噪声多学科优化设计与试验验证。采用基于涡格法的升力面理论进行螺旋桨气动性能计算，基于Hanson频域远场噪声计算方法进行螺旋桨远场噪声评估，2种计算方法都通过与试验对比验证精度，由此组成螺旋桨气动-噪声联合算法；以桨叶沿叶高分布的弦长、安装角和侧掠为设计变量，充分考虑桨叶结构强度对设计变量的约束，以螺旋桨推力、效率不降低和远场噪声降噪最大为优化目标；优化桨叶通过了离心载荷试验、气动载荷试验、动态特性试验等强度试验；在气动声学风洞内完成了气动与声学性能验证，优化螺旋桨相比原始桨气动性能基本保持不变，优化螺旋桨在设计工况的1阶离散分量处的远场气动噪声峰值降低2.7dB，较小推力下降噪量最高可达4dB，2阶离散分量处也有明显的降噪效果。提出的方法同时满足气动、噪声和结构强度要求。

Abstract:

In order to reduce the noise of aircraft propellers， multi-disciplinary design and experimental verification for a certain low noise aircraft propeller that comprehensively considers aerodynamic， noise and structural strength were carried out. A joint algorithm for propeller aerodynamic/aeroacoustic performance was proposed， in which lifting surface theory based on the vortex lattice method was applied for propeller aerodynamic performance calculating， and Hanson frequency domain far-field noise calculation method was employed in propeller far-field noise evaluation. Both of these methods were validated with experiments and formed as a joint optimal algorithm. Distribution of chord， blade angle and side sweep along the blade height were made as design variables for the optimization. The constraints of blade structural strength on design variables were fully considered. The objective was to maximize the noise reduction in the far field without sacrificing the propeller aerodynamic efficiency and thrust. The optimized blades were verified by the structural strength， which were centrifugal load experiment， aerodynamic load experiment and dynamic characteristic experiment. The aerodynamic and aeroacoustic experiments were carried out in the aeroacoustic wind tunnel. The experimental results of the optimal propeller indicated similar aerodynamic performance with that of basic propeller. The far-field aerodynamic noise peak of the optimal propeller at the first-order discrete component of the design condition was reduced by 2.7dB. Noise reduction was up to 4dB under smaller thrust. A significant noise reduction at second-order discrete component were also observed. The method proposed in this paper meets the requirements of aerodynamics， acoustic and structural strength at the same time.