Application of high-robustness BEMT for simulation of UAV-VTOL propeller at low/high advance ratio

For UAV-VTOL propeller design, lots of nonlinear effect should be considered such as low-Re, transonic and large AOA effect. On the other hand, when considering the propeller-wing interaction in the design, the flow details of the propeller, such as circulation, should be obtained. The basic Blade Element Momentum Theory (BEMT) has difficulty analyzing propellers at Low/High advance ratio. In this paper, an improved BEMT is presented for nonlinear wide-range propeller analysis. First, the artificial Neural Networks are used to establish the airfoil performance evaluating model. Second, the BEMT was refined by circulation iteration and is able to analyze propeller at both low/high advance ratio robustly. Third, the analysis examples are presented to shown the accuracy and robustness of the refined BEMT. At last, the inversed BEMT for propeller design is present.