超声速来流基元叶型前缘加工误差气动敏感性分析

Aerodynamic Sensitivity Analysis of Manufacturing Errors for Leading Edge of Supersonic Elementary Blade Profile

关键词:  叶栅  气动性能  转子  前缘误差  正交实验  敏感性

Key words:  Cascade  Aerodynamic performance  Rotor  Leading edge error  Orthogonal experiment  Sensitivity

摘要:

为研究叶型前缘加工误差对叶栅气动性能敏感性，以NASA Rotor 67转子70%叶高截面基元级叶型为研究对象，选择Clamped型非均匀B样条曲线实现叶型前缘数学描述。采用单因素法建立叶型前缘加工误差模型，提炼出叶片弦长误差、前缘轮廓度误差、几何进气角误差三个误差模型；随后结合L₉(3⁴)正交实验及数值模拟方法研究超声速来流条件下三维直列叶栅不同前缘误差类型对叶栅气动性能的敏感性。正交实验极差分析及显著性分析均表明：前缘轮廓度误差F_P是影响叶栅气动性能的主要影响因素(75%以上可能性)，叶栅性能随前缘轮廓度增加呈现恶化趋势，即叶型前缘越厚，叶栅总压损失越大，扩压能力越小。进一步分析轮廓度误差对叶栅性能影响机制得出：激波损失是叶栅性能随轮廓度误差加大而恶化的重要原因。

Abstract:

The present study took 70% span elementary blade profile of NASA Rotor 67 as a research object in order to investigate the aerodynamic sensitivity of blade leading edge manufacturing errors. The Clamped non-uniform B-spline curve was selected to achieve a mathematical description of the leading edge of the elementary blade. Three leading edge error models were extracted using single-factor method, and the error models were as follows: chord error, leading edge profile error, and geometrical inlet angle error. Then the L₉(3⁴) orthogonal experiment and numerical simulation method were adopted to study the aerodynamic sensitivity of different leading edge error models to the aerodynamic performance of the three dimensional supersonic straight cascade. The range analysis and significance analysis of orthogonal experiments both show that the leading edge profile error is the main factor that affects the aerodynamic performance of the cascade (more than 75% possibility). The performance of the cascade deteriorates with the increase of the profile of the leading edge, that is, the thicker the leading edge of the blades, the larger the total pressure loss and the smaller the diffusion capacity. Further analysis of the aerodynamic influence mechanism of the profile error shows that the shock loss is the main reason for the deterioration of the cascade performance with the increase of the profile error.