On Site Testing of a Zero Head Vertical Axis Helical Water Turbine for Power Generation

The need of an efficient, low cost and environment friendly hydraulic energy converter provides motivation to many researchers to contribute in the field of renewable energy. In the present investigation, one such requirement is addressed for the possibility of electrical power generation from free stream of water. The implementation of such a low head or zero head turbine does not require a dam for energy conversion, thereby making it a low cost and environmental friendly source of power generation. The present study deals with the development of a zero head vertical-axis helical water turbine, and its subsequent testing in an open channel. The main parameters that influence the performance of a helical water turbine are its blade profile, aspect ratio, helix angle, number of blades and solidity ratio. Considering these parameters and the numerical work reported in literature, a three-bladed helical turbine has been developed and tested under different loading conditions. The variation of power coefficient at various tip-speed ratios of the turbine has been investigated and analyzed.