Effects of Blade Design Parameters on The Performance of a HAWT

Abstract

In view of the increasing concerns about wind energy exploitation as one of the promising alternatives of renewable energy systems, numerous efforts are directed to rotor blades design in order to achieve the best performance. Forces acting on rotor blades of horizontal axis wind turbine (HAWT), and hence the turbine power coefficient, are greatly affected by deviations in blade profile shape and surface roughness from design conditions. Both may change due to environmental impacts such as dust, sand, ice…etc. One of the methods proposed for restoring performance of blades suffering from such changes is to attach a winglet at the tip of the blades. The present work examined the winglet effect on blade performance at different operating conditions. An experimental study on a model of HAWT was carried out at the project laboratory to investigate the winglet positive effect on power coefficient. Blades are tested in six modes namely; cleansurface with and without winglet, rough surface with 1-mm and 3-mm heightmodels and rough surfacewith 1-mm and 3-mm heightmodels provided withwinglet. Primary variables were measured at different air speeds and blade angles of attack, and performance parameters were deduced. A remarkable improvement in power coefficient was generally obtained.