Design and Performance of a Double-Pitch Wind Turbine with Non-Twisted Blades

A new design has been proposed for inexpensive wind turbine blades with high power coefficients. The new wind turbine blade has been subdivided into two, each with a different pitch angle, to optimize aerodynamic flow, absence of twist, and carries a variable chord along the blade itself. The new blade reveals some energy loss due to the tip vortices of each blade part (which can be minimised by winglets), yet proves that it is possible to create a wind turbine with high power coefficients. To design and evaluate the performance of the new wind turbine a numerical code, developed by the authors and based on blade element momentum theory, was implemented after validation by experimental measurement found in scientific literature. The code led to better choices of layout to maximize turbine performance.