翼身融合布局民机高低速协调设计

翼身融合（BWB）布局作为一种创新的布局形式，成为未来民用飞机发展的热点。与传统布局相比，BWB布局具有综合优势，是以安全性、经济性、舒适性和环保性为发展目标的下一代大型民用飞机的理想布局。针对BWB布局低速飞行性能不易满足"绿色航空"发展目标的技术现状，分析当前BWB布局高低速综合设计中出现的问题和面临的挑战，提出了改善低速性能的应对策略。通过总体参数对高低速性能的影响规律研究，分析了影响高低速协调设计的各种因素，指出翼载是影响高低速协调设计的核心参数。基于项目组长期研究工作，提出了综合考虑高低速性能的BWB布局设计要求，建立了高速向低速适当妥协，综合平衡高低速矛盾的设计思想，给出了由三点技术措施构成的高低速协调设计原则。根据本文提出的高低速协调设计思想和设计原则，采用多学科综合优化和气动综合设计方法，进行了概念方案的高低速协调设计，获得了高低速协调、综合性能优异的概念设计方案。CFD分析和风洞试验验证结果表明，协调设计后的概念方案，在保持优异巡航性能的同时，显著提高了低速性能，降低了对增升能力的需求，减小了高升力状态力矩平衡措施的设计压力，达到了保证巡航效率和提升低速性能的协调设计目标。本文提出的高低速协调设计思想和设计原则为提升BWB布局低速性能提供了新的思路和方法，可应用于翼身融合类民机布局研究，并可为其他用途翼身融合类飞机设计提供参考。

Tradeoff design of high and low speed performance for blended-wing-body civil aircraft

As an innovative configuration, the Blended-Wing-Body (BWB) configuration has become a worldwide research focus in civil aircrafts development. Compared to the conventional configuration, the BWB shows integrative benefits and becomes the most promising candidate for a safe, economical, comfortable, and environmentally friendly large aircraft. This paper emphasizes the fact that the present BWB designs focus on the high speed transonic performance but pay less attention to the low speed characteristics, which leads to the design challenge that the low speed characteristics of BWB configuration can hardly satisfy the severe requirement of "green aviation" for the next generation of aircrafts. To solve this problem, a tradeoff design method for high and low speed performance has been put forward. By analyzing the effects of conceptual design parameters, the wing loading is chosen as the primary parameter to coordinate low and high speed performance. Based on previous studies, a tradeoff design principle consisting of three main technological components has been proposed to balance the conflict between high and low speed performance. A multi-disciplinary design optimization platform is applied to obtain a tradeoff design for both cruise performance and low speed requirements. The CFD and wind tunnel results show significant improvement of low speed performance while maintaining high speed performance. This result is suitable for relieving the pressure of high-lift devices and control surface design, achieving both the cruise efficiency and the required high lift. The methods proposed in this study provides new designs and methods for improving BWB low speed performance, which can be applied to the further study of the BWB civil aircrafts and provide useful information for other applications.