The performance of different vertical axis wind turbines with j-shaped blades

Abstract

This study is focused on the aerodynamic optimization of Vertical Axis Wind Turbines' blades. A special feature was investigated – the opening at the blade’s trailing edge (opened blades). The blades having this element are known as J-shaped blades. The analysis was done experimentally by testing eleven small scale turbines which were organized into four sets. The performance was compared within each set which contained both full and open bladed turbines. Two airfoil types were examined: symmetrical NACA 0018 and asymmetrical FX 63-137, and two types of blades: straight and helical. The compared turbines had the same key parameters and were subjected to the same external conditions. The tendencies clearly favored the J-shaped turbines for all cases. Besides superior productivity, the open bladed turbines started generating power from lower wind speeds. The positive effects of the openings were not the same for all examined cases and were influenced by the airfoil type, blade shape, openings orientation and wind speed.