Study on Cruise Drag Characteristics of Low Drag Normal Layout Civil Aircraft

低阻常规布局客机巡航阻力特性研究

School of Aeronautics, Northwestern Polytechnical University, Xi'an 710072, China

Received: 12 July 2019

Abstract

This paper focus on the wing shape related drag reduction measures of normal layout civil aircraft, through the drag reduction to improve the aircraft performance. Mainly by the laminar flow wing to reduce skin drag and weak shock wave wing to reduce shock drag, to keep a section of laminar zone on the wing leading edge to reduce skin drag, the wing profile's pressure distribution transit from the middle part's tonsure pressure zone to the trailing edge's inverse pressure gradient zone gentle to reduce the shock drag. The wing body junction plus the body belly fairing to increase the junction flow velocity, through increase flow velocity to weak the boundary layer stacked at the junction, improve the drag performance. The blended winglet to reduce the wing tip induced drag, study the shape parameters impact on the drag reduction, longitudinal moment and directional moment, attain the winglet model with drag reduction effect, suitable pitching moment and directional moment. For the wing body fairing have significant impact on the wing shape lower surface pressure distribution, the winglet have important impact on the wing tip flow, so the single part drag reduction measure is not feasible, need to carry out integrated drag reduction study on the wing related three drag reduction measures, and study the drag reduction measure's drag reduction decrement, put a reference for the normal layout civil aircraft's drag reduction. Through the above drag reduction measure's assessment attain the effect of drag reduction and rising the normal layout civil aircraft's cruise ratio, improving the cruise performance.

摘要

对常规布局客机与机翼相关的减阻措施进行研究，通过减阻改善飞机性能。主要通过有层流流动机翼减小摩阻和弱激波机翼减小波阻，在机翼表面前缘维持一段层流区以减小摩阻，机翼剖面压力分布由中部顺压梯度区域向后缘逆压梯度区域和缓过渡形成弱激波减小激波阻力；机翼机身结合处加机身腹部整流增加结合处流速，减弱机翼机身结合处的附面层堆积，改善阻力性能；融合式翼梢小翼降低翼尖诱导阻力，研究小翼外形参数对降低诱导阻力、纵向力矩、偏航力矩的影响，得出降低翼尖诱导阻力效果好、力矩合适的翼梢小翼模型。由于翼身整流对机翼内翼段下表面的压力分布有显著影响，翼梢小翼会对翼尖的流动有重要影响，因此进行单方面的减阻是不可取的，需对与机翼相关的3种减阻措施进行一体化减阻设计研究，并对相应的减阻量进行评估，为常规布局类客机的减阻设计提供参考。通过对上述减阻措施的评估分析达到了减小阻力、提高常规布局客机巡航因子，改善飞机巡航性能的效果。