Design improvement of the Water-rotor Hydrokinetic Turbine to Extract Energy from River Flows and Water Transfer Channels

Nejadali, Jafar; Chaghamirza, Sina

doi:10.22034/a-see.2025.2071106.1010

Design improvement of the Water-rotor Hydrokinetic Turbine to Extract Energy from River Flows and Water Transfer Channels

Document Type : Original Article

Authors

Jafar Nejadali

Sina Chaghamirza

Department of Mechanical Engineering, University of Mazandaran

10.22034/a-see.2025.2071106.1010

Abstract

Hydrokinetic turbines are environmentally friendly systems located in river streams that convert the kinetic energy of water flow into electrical power without the need for a dam. However, due to the low efficiency of these turbines, existing designs are still in the development phase. This study optimizes water-rotor turbine designs—a horizontal-axis, cross-flow variant of Savonius turbines—by simulating six configurations varying blade count (2 or 3) and hub diameter (200-400 mm) at Re=450,000 using ANSYS Fluent with transient k-ω SST turbulence modeling and mesh motion. Three-dimensional finite volume simulations reveal that two-blade designs achieve higher peak power coefficients (Cp-max=0.138 at TSR=0.8 for 200 mm hub) than three-blade ones (Cp-max=0.114 at TSR=0.6), with smaller hubs enhancing performance by maximizing blade cup area. Segmenting the turbine and rotating the rear half by 90° further boosts efficiency to 14.5% at TSR=0.8, outperforming the baseline by 5%. Flow analysis shows reduced wake turbulence and prolonged fluid-blade interaction as key mechanisms, with velocity recovery over 4D downstream informing array spacing. These findings advance dam-free hydropower for rivers and channels.

Keywords

Hydrokinetic System

Numerical Simulation

Optimization

Water rotor

Hub

Subjects