Computational Analysis of Performance of Helical-Bladed Hydrokinetic Turbine

The exploration of green energy sources is gaining considerable attention due to increased demand for energy and serious environmental concerns. Hydrokinetic technology, among such sources, harnesses the energy from free-flowing water using a hydrokinetic turbine (HKT) for small-scale hydropower generation. Among various hydrokinetic turbine designs, the helical-bladed HKT can be deployed in rivers, canals, tidal estuaries and ocean currents. The present study aims to analyze the performance of a helical-bladed HKT rotor for different water velocities (0.5, 1.0 and 1.5 m/s) in an open channel using computational analysis. Furthermore, the flow over rotor blades has also been analyzed. A three-bladed helical turbine rotor having NACA 0020 hydrofoil as blade profile, solidity of 0.20 and aspect ratio of 1.0 is modeled with a rotor model simulated using RNG k-ε turbulence model. The pressure and velocity contours are plotted and discussed based on computational simulations. The maximum power coefficient of helical turbine is observed to maintain the same value (~0.36) for given water velocity of 0.5–1.0 m/s and then declines beyond 1.0 m/s. Also, the torque coefficient decreases with tip speed ratio (TSR) value, follows a similar trend for given flow velocities and attains a maximum value (=0.292) corresponding to TSR value of 0.5 and flow velocity of 0.5 m/s. However, more investigations are required to recommend for its real applications.