Aerodynamics optimum design procedure and program for the rotor of a horizontal-axis wind turbine

Abstract

A design procedure and its computer program using aerodynamic optimization for the rotor of a horizontal-axis wind turbine is presented in this paper. It is based on the method of prediction of aerodynamic characteristics for the air-screw by the so-called “blade theory” and according to the feature of the flow around the rotor. Design methods now being widely employed are based on so-called “disk theory”, by which a vortex system with the assumption of an infinite number of blades is the aerodynamic model of the rotor. The influence of the number of blades has to be considered and evaluated according to some consideration. This will introduce a certain inaccuracy in the aerodynamic calculation of the rotor. In this paper, abandoning the assumption of an infinite number of blades, a vortex system adopted in this design method is able to give the induced downwash velocity at blade sections so that more accurate aerodynamic forces can be obtained. The power coefficient of the rotor is taken as the objective function for aerodynamic optimization to give an optimal geometry of the rotor. The design rotors which are of high efficiency and good performance are given. Comparison of their calculated and experimental performances shows good agreement.