Performance investigation of self-adjusting blades turbine through experimental study

In the quest for renewable energy sources and sustainable development, hydrokinetic energy available in marine currents, river currents, water flows and man-made canals should be harnessed. This is particularly true for rural and remote areas, which have access to water but often have poor electricity. The vertical axis current turbine, which is a key hydrokinetic technology, has been greatly improved over the last few years. It has numerous advantages, including independency of flow direction, design simplicity, quiet operation, no required yaw mechanism and low cost. The Savonius hydrokinetic turbine is one of the most important drag-type configurations of a vertical axis current turbine. However, it suffers from negative torque, negative drag force on the returning blades, low efficiency and difficulty interfacing with a generator. This paper proposes a novel drag based vertical axis current turbine using arms and self-adjusting blades. This novel design was developed based on the framework of a Savonius hydrokinetic turbine. In an effort to decrease the hydrodynamic resistance of the returning blades and increase the total output torque of the turbine, this study aims to investigate the performance characteristics of a novel vertical axis current turbine (hereinafter referred to as "self-adjusting blade turbine"). Experimental tests were conducted in the Universiti Teknologi Malaysia (UTM) at low speed currents to assess the performance characteristics of three configurations of a fixed blade turbine and a self-adjusting blade turbine. The force acting on one blade of the self-adjusting turbine was analysed in detail. The results showed that the arm length and blade angle affected the performance of turbine, and that there was 30.7% increase in performance for the self-adjusting blade turbine compared to the fixed blade turbine.