曲率连续的非轴对称短舱气动型面参数化设计方法研究

Parametric Design Method for Aerodynamic Profiles of Continuous Curvature Non-Axisymmetric Nacelle

关键词:  涡扇发动机  曲率连续  非轴对称短舱  参数化设计  类别形状函数

Key words:  Turbofan engine  Continuous curvature  Non-axisymmetric nacelle  Parametric design method  Class shape transformation function

摘要:

为了进一步提高短舱内外流的气动性能，基于类别形状函数方法建立了曲率连续的非轴对称短舱气动型面参数化设计方法。为评价所建立的短舱气动型面设计方法的适用性，从曲率半径分布、关键工况下的流动特性和气动性能三个方面对使用所建立的方法和基于圆锥曲线方法设计的超大涵道比短舱进行了对比研究。结果表明：与基于圆锥曲线方法设计的短舱相比，所建立的方法设计的短舱不存在轴向曲率半径波动。由于消除了曲率波动引起的短舱壁面附近局部过度加速形成的高速低压区，在马赫数为0.8的巡航条件下外罩壁面局部阻力降低了4.5%；在马赫数为0.82的飞行工况下，外罩壁面局部阻力降低了5.5%。进气道气动型面设计方法的改进，使得大攻角爬升条件下进气道总压恢复系数提高了0.41%，稳态周向总压畸变指数减小了8.82%。

Abstract:

In order to improve the internal and external performance of nacelle， the parametric design method for the aerodynamic profiles of continuous curvature non-axisymmetric nacelle， based on Class Shape Transformation function， was developed. To evaluate the parametric design method for the aerodynamic profiles of non-axisymmetric nacelle， the curvature radius distribution， flow characteristics， and aerodynamic performance of the ultra-high bypass ratio turbofan nacelle designed by the method developed in this paper and designed by the method based on conic curve were compared. In comparison to the nacelle designed by the method based on the conic curve， there is no fluctuation in the distribution of curvature radius in the axial direction for the nacelle by the method developed in this paper. The local drag around the maximum area cross-section of the nacelle designed by the method developed in this paper decreases by 4.5% in cruise condition， that free stream Mach number is 0.8 and decreases by 5.5% in the condition that the free stream Mach number is 0.82. The reason for this is that the local high-velocity zone caused by fluctuations in the curvature radius around the maximum area cross-section of the cowl is avoided. Compared with the nacelle designed by the method based on the conic curve， the total pressure recovery coefficient of intake increases by 0.41% and the steady circumferential distortion index of total pressure decreases by 8.82% in climb condition with high angle of attack， due to the improved design method of intake.