The delta-wing bladed rotor concept

Abstract

A description is given of a new type of horizontal axis wind-turbine rotor incorporating sharp-edged, flap-equipped, fixed pitch, delta-wing-like blades. It is shown that rotors of this type can attain a maximum torque coefficient at zero tip-speed ratio whilst achieving a maximum power coefficient of 0.43 at a tip-speed ratio of approximately 1.7: the runaway tip-speed ratio is about 3.2. Applications of the delta-wing-bladed rotor concept to both water pumping and electric power generation are discussed. It is shown that the new form of rotor is particularly suited for water pumping duties. It is also shown that it has potential for electrical power generation applications in situations where the rotor noise of conventional wind-electric machines is a major problem. A very low tip-speed ratio version of the delta-wing-bladed turbine is also described briefly. The latter form of rotor was conceived especially for the task of driving reciprocating deep-well pumps without the intervention of reduction gearing between the turbine shaft and the pump.