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.