垂直軸風車における翼取付位置の影響に関するCFD解析

抄録

The blade-install-position of a lift-type vertical-axis wind turbine (VAWT) is theoretically set at the aerodynamic center (25%c). However, some practical VAWTs often select the center of mass of a blade cross section as the install-position or the other position. This study analyzes the effects of the blade-install-position on the performance of two-bladed VAWTs by two-dimensional computational fluid dynamics (CFD). Two turbine rotors with the diameter D = 10 and 2 m are selected as the numerical models. The blade-install-positon defined by x_install / c ×100 (x_install is a distance from the leading edge) is set at five values of 0, 25, 50, 75, 100%c for each rotor (chord length : c = 0.4 or 0.2 m) under the condition holding a constant pitch-angle of 0°. In the case of a large rotor (D = 10 m), the optimum tip speed ratio (TSR) is about 4.5; and the blade-install-position does not affect the output performance greatly at the optimum TSR or more. In the case of a small rotor (D = 2 m), the optimum TSR is about 3; and the blade-install-position gives a great influence on the turbine performance around the optimum TSR. The change in the blade-install-position gives rise to the effective pitch-angle even when keeping a constant geometrical pitch-angle. The difference of the influence of the blade-install-position on the performance between the large and small rotors can be attribute to the difference in the ratios of the chord-length to the rotor diameter of both turbines (c/D = 0.04 and 0.1).