Improved Blade Element Theory and Autorotating Rotor Aerodynamic Characteristics Analysis

Abstract

: During forward flight, the flow field of autorotating rotor was very complicated, which caused induced velocity of the disc plane difficult to be obtained. In order to analyze aerodynamic characteristics of the autorotating rotor, improved blade element theory, using the unlimited-bladed fixed wake method to establish a mathematical model, which could obtain velocity of the disc plane induced by fixed wake of autorotating rotor. According to the Biot-Savert Theorem, the expression of axial induced velocity of disc plane could be got by integerating. The circulation and induced velocity were all expanded into Fourier series by azimuth, and then axial induced velocity could be carried out by iteration. Combined the blade element theory, aerodynamic forces of the autorotating rotor was obtained, and then analyzed its aerodynamic characteristics.