Experimental and computational evaluation of Savonius hydrokinetic turbine for low velocity condition with comparison to Savonius wind turbine at the same input power

摘要

The extensive depletion of the conventional sources of energy has forced the mankind to explore every possibilities lying beneath the nature. The evolution and modification of the old ideas from the field of wind turbine led the mankind to explore the same technology in water. Hydrokinetic turbine, one of the most emerging technologies for power generation, has gained keen interest of the researchers because of some of the unique properties of water like higher specific weight, higher momentum than air for same velocity etc. The objective of the study is to evaluate how the conventional Savonius wind turbine performs when it rotates by the momentum of water current at low velocity from 0.3 m/s to 0.9 m/s in an open water channel. An experimental investigation along with computational fluid dynamics (CFD) study using Ansys 14.0 has been carried out to accomplish the objective of the work. To understand the significance of Savonius design in water application, the performance of the hydrokinetic turbine is experimentally compared to the identically designed wind turbine for the same input power values, showing enhanced performance of the former turbine. The purpose of using CFD is to enable a more detailed study on the velocity and torque distribution across the hydrokinetic turbine and hence to develop more insight of design information about its performance under low velocity condition. Finally the reason for enhanced performance of the hydrokinetic turbine is investigated from the computational study of flow characteristics of both the hydrokinetic and wind turbines. Smooth, stable operation and a good service life of the hydrokinetic turbine could be expected unlike the wind turbine.