Behavior Analysis of Vertical Axis Water Turbine with Individual Blade Pitch Control

Abstract

H-rotor type vertical axis water turbine has received the attention of recent researchers due to its ability to perform better than other competitive turbines. But simple H-rotor type vertical axis water turbine do not perform well due to its constantly changing angle of attack during the course of its rotation. Different pitching mechanisms have been suggested by the researchers over the time to enhance the performance of H-rotor type vertical axis water turbine but sinusoidal pitching mechanism, though it is less efficient, has proved itself to be practically implementable. Furthermore, sinusoidal pitching mechanism can only increase efficiency at low tip speed ratios. To cope with situation and to increase the efficiency of such turbines, this study introduces a new pitching mechanism which, in fact, is a slight modification of simple sinusoidal pitching mechanism. Numerical analysis of the suggested pitching mechanism have shown that it can increase the efficiency of the turbine at all tip speed ratios.