基于太阳能飞机应用的低雷诺数翼型研究

以太阳能飞机为背景,对低雷诺数翼型FX 63-137进行了折线型建模以拟合典型晶硅太阳能电池片对气动外形的影响,开展了气动数值模拟分析。首先引用"拟合优度"的定义描述本文折线型翼型轮廓与基准翼型(Baseline)的吻合度,并以此参数为变量建立5种折线型翼型模型;然后,采用计算流体力学(CFD)方法计算分析了不同雷诺数下各折线型翼型的气动特性,并着重研究了低雷诺数下折线型翼型的绕流机理;最后,基于工程应用实际的需求,提出了晶硅太阳能电池片的铺设方法也即折线型翼型设计思想准则,并进行算例验证。研究结果表明:低雷诺数条件下,折线型翼型升阻性能相比光滑翼型在一定程度上表现出了优势,但随着雷诺数的增加,升阻方面的优势逐渐消失;折线型翼型压力分布受各折线段长度影响,前缘吸力峰值、压力平台范围以及压力恢复区分布特征是决定折线型翼型气动性能的主要因素;通过设计的算例验证了本文提出的折线型翼型设计思想的可行性。

Research on low Reynolds number airfoils based on application of solar-powered aircraft

Based on solar-powered aircraft,numerical simulation is carried out for broken line airfoils modeled with typical low Reynolds numbers FX 63-137 airfoil to simulate the influence of typical crystalline silicon solar cells on aerodynamic shape.The definition of "goodness of fit" is used to describe the degree of matching between broken line airfoil profile and the reference airfoil (Baseline).Five broken line airfoils with different goodness of fit are established.With computational fluid dynamics (CFD) method,the aerodynamic characteristics of different broken line airfoils at different Reynolds numbers are analyzed,and the flow mechanism of the broken line airfoil is studied in particular.Based on the actual needs of engineering applications,the method of laying sheets of crystalline silicon solar cells,which is also the design criteria of broken line airfoil,is proposed,and examples are used to verify the effectiveness of the method.The results show that the aerodynamic performance of broken line airfoils is better than that of the baseline airfoil at low Reynolds number to some extent.However,with the increase of the Reynolds number,advantages of broken line airfoils in lift and drag performance disappear.Pressure distribution of the broken line airfoil is influenced by the length of broken lines and leading edge suction peak,region of pressure plateau and distribution in pressure recovery zone are the main factors determining the aerodynamic performance of broken line airfoils.The proposed design criteria for broken line airfoils are verified through designed examples.