Center Body Airfoil Design for Blended Wing Body Configuration

Peifeng Li,Zhenli Chen,Yujin Tao,Dong Li,Binqian Zhang

doi:10.1051/jnwpu/20183620203

Abstract

To design the center-body airfoil of a blended wing body configuration, the aerodynamic effects of the symmetrical airfoil, trailing-edge reflexed airfoil, leading-edge loaded airfoil and leading-edge loaded plus trailing-edge reflexed airfoil are investigated based on the constraints of system arrangement. A 150-passenger BWB configuration is studied; for a center-body with symmetrical airfoil, the larger outer-wing geometrical twist should be used to fulfill the positive zero-lift pitching moment according to the design requirements of longitudinal static stability, however, lift to drag ratio shows a big decrease. For leading-edge loaded airfoil, it is difficult to achieve a positive zero-lift pitching moment because of the platform limitation. For trailing-edge reflexed airfoil or leading-edge loaded plus trailing-edge reflexed airfoil, it is easy to achieve ideal design results when reasonably designing the leading-edge loading and trailing-edge unloading. The application of a blended wing body UAV shows that the loss of aerodynamic characteristics is small when adopting the "eagle hook" stealth leading edge that has the characteristics of leading edge loading.

Highlights

trailing⁃ edge reflexed airfoil are investigated based on the constraints of system arrangement
fulfill the positive zero⁃lift pitching moment according to the design requirements of longitudinal static stability
The application of a blended wing body UAV shows that the loss of aero⁃ dynamic characteristics is small when adopting the

Summary

Introduction

李沛峰1, 张彬乾2, 陶于金1, 陈真利2, 李栋2 (1.西北工业大学无人机研究所, 陕西西安 710065;2.西北工业大学航空学院, 陕西西安 710072) 摘要:针对翼身融合布局中央机体翼型设计,在满足总体装载约束条件下,研究对称翼型、后卸载翼型、前加载翼型和前加载-后卸载翼型的气动影响规律。 150 座级 BWB 布局研究结果表明,采用对称翼型时,外翼需采用较大的负几何扭转角以实现静稳定设计状态下的正零升力矩,但升阻性能损失较大;采用前加载翼型时,受布局平面形状限制,不易达到正零升力矩;采用后卸载翼型或前加载-后卸载翼型时,合理设计前加载或后卸载的区域及大小,可获得升阻及力矩特性较为理想的气动设计结果。翼身融合飞翼布局无人机应用研究表明,采用具有前加载特征的" 鹰勾" 隐身前缘设计,气动性能损失小。翼身融合布局( blended wing body,简称 BWB) 作为一种综合性能突出的新型布局形式,将成为未来军民用航空领域飞行器发展的必然趋势[1⁃2] 。突出高升阻比、高巡航效率的 BWB 布局与常规布局有很大的不同。一方面,需要追求高升阻比以提高飞机的巡航效率;另一方面,需要追求飞行边界内的安全特性,特别是巡航状态下的力矩配平特性。从气动力设计角度, 这两个问题往往是相互矛盾的。为了兼顾高升阻比与配平及操纵能力,则必须从气动布局形式和翼型设计两方面去加以权衡。在布局形式确定的前提下,翼型与机翼设计是提高飞机升阻比的最主要途径。目前,BWB 中央机体翼型主要采用大厚度的后卸载翼型( 或反弯翼型)、前加载翼型和其他类翼型。大厚度后卸载翼型( 相对厚度大于 15%) 可提

Results

Conclusion