Case study of a cross-flow hydrokinetic turbine in a narrow prismatic canal

Abstract

The performance of a high-solidity H-Darrieus cross-flow hydrokinetic turbine was tested in the subcritical flow of a narrow artificial canal. Turbine shape and swept area were selected to generate high blockage into the flow for mechanical power maximization, although a high axial thrust on the blades was attained. A detailed description of the support structure, probes, and the turbine is provided as a first step of further in-depth studies. After measurements of the undisturbed flow velocity with an acoustic doppler velocimeter, the turbine was submerged to operate at different rotor speeds, while measurements of torque, thrust, and rotor speed were acquired. The water depth at another crossbar was measured continuously to check the backwater profile spreading towards upstream, showing no flooding risk at each rotor speed. Experimental data were analyzed for the torque ripple investigation and high sensitivity to low tip speed ratios was demonstrated.