The performance of simple horizontal axis wind-turbines for the direct drive of water pumps

Two turbine types were considered. Interest in both types, Cretian compliant-sail bladed machines and turbines with multiple flat slats as blades, has recently been revived, in developing nations, for water pumping applications. The work was based on wind-tunnel tests the results of which are presented in the form of power and torque coefficients versus velocity ratio. It was shown that a Cretian turbine can attain a maximum power coefficient of approximately 0.28 and also achieve a high starting torque. It was also found that optimised slatted wind-turbines are limited to maximum power coefficients of 0.19 to 0.23 depending upon their construction. The present results were combined with those of an earlier paper to yield what is believed to be a comprehensive summary map of the operational characteristics of optimised horizontal axis wind-turbines for the direct drive of water pumps.