低雷诺数多螺旋桨/机翼耦合气动设计

以临近空间太阳能无人机研究为背景，针对高空低雷诺数状态下多螺旋桨/机翼构型进行了耦合气动设计研究。首先，通过对典型多螺旋桨/机翼构型进行气动特性及流动特性分析，提出了以在多螺旋桨滑流影响下构建机翼近壁面理想流态分布形式为核心的低雷诺数多螺旋桨/机翼耦合气动设计思想；然后，基于该耦合设计思想，依次进行了多螺旋桨布局参数设计研究、低雷诺数流态区域二维翼型设计研究以及近似高雷诺数流态区域耦合螺旋桨滑流影响的机翼翼段设计研究；最后，通过相关设计结果的对比分析验证了所提出低雷诺数多螺旋桨/机翼耦合气动设计思想及设计方法的有效性和可靠性。结果表明：与常规仅进行低雷诺数翼型优化得到的设计结果相比较，基于所提出低雷诺数多螺旋桨/机翼耦合设计思想设计得到的多螺旋桨/机翼构型气动特性得到显著改善，在设计状态下，多螺旋桨滑流影响下的机翼阻力相对降低达8.8%，升阻比相对增大达12.1%，由多螺旋桨滑流为机翼气动特性带来的不利影响亦得到约64.5%的补偿和改善。

Multi-propeller/wing coupled aerodynamic design at low Reynolds number

Based on the research of near-space solar-powered unmanned aerial vehicles, the multi-propeller/wing integrated aerodynamic design at high altitude and low Reynolds number is studied. With the analyses of both aerodynamic per-formance and flow characteristics of the typical multi-propeller/wing configuration, a concept for the low Reynolds number multi-propeller/wing coupled aerodynamic design is proposed, which is based on the construction of ideal near-wall flow distribution under multi-propeller-induced effects. And then, the multi-propeller parameters, the sectional airfoil within low Reynolds number regions, and the wing section within higher Reynolds number regions are optimized and studied in sequence. Lastly, both the reliability and efficiency of the proposed multi-propeller/wing coupled aerodynamic design concept are studied by analyzing the optimized results. It shows that the aerodynamic performance of the configuration designed based on the proposed concept is significantly improved when compared with the conventional designed based on optimization of the airfoil at the low Reynolds number. The wing designed based on the proposed coupled processes has a relative drag reduction of 8.8% and a relative lift-to-drag ratio increment of 12.1%, and nearly 64.5% adverse effects induced by the multi-propeller slipstream can be eliminated.