Experimental study on kinetic energy conversion of horizontal axis tidal stream turbine

Abstract

a b s t r a c tThe present study aims to understand the energy conversion mechanism of a 100 kW horizontal axis tidal stream turbine by analyzing thrust, torque, and wake flow measurements. The scale ratio of the turbine model was 1/20 and model tests for power and wake measurements were conducted in a towing tank facility. Wake fields were measured by a towed underwater stereoscopic particle image velocimetry (SPIV) system. The chord-length based Reynolds number at 40% of the radius of the turbine ranged from 53,000 to 63,000 in the test conditions. The turbine model showed the highest power coefficient at a tip speed ratio (TSR) of 3.5, and the magnitude of power coefficient was 0.278. Three TSR conditions were selected for SPIV measurement after power measurement tests, representing heavy loading, highest efficiency, and light loading, respectively. In the wake field measurement results, conversion of kinetic energy of the turbine wake was investigated, decomposing it into effectively extracted work, loss due to the drag on the turbine system, kinetic energy of the time-mean axial flow, local flow structures, turbulence, and secondary flow loss. In high TSR conditions with a small angle of attack onto the turbine blade, the secondary flow loss was minimized.

An investigation of the applicability of SPIV for the analysis of the dynamics of floating offshore wind platforms

“…Moreover, the equipment in this technique does not interfere with the fluid flow. To date, the use of underwater S-PIV in tank tests has been limited to the study of ship propellers (Go et al, 2019), tidal stream turbines (Seo et al, 2016), the ship model wave field (Mallat et al, 2015), (Jacobi et al, 2016), (Tukker et al, 2000) and basic phenomena such as vortex-induced vibrations (Ashworth Briggs et al, 2019). There are successful attempts in the literature to use this technology to create a high-fidelity ship manoeuvring database (Yoon et al, 2015).…”

A review on the technologies, design considerations and numerical models of tidal current turbines

“…The principal objective of hydrofoil conception is to increase the coefficient of lift and to 275 reduce the coefficient of drag and the coefficient of pitching moment [90]. In order to find the 276 most appropriate condition for the hydrofoil operation for a given profile section, the lift-to-277 drag ratio is one of the key performance feature.…”

Computational Analysis of the Performance of a Vertical Axis Turbine in a Water Pipe

“…We used the same pipe diameter and inflow velocity, thus the power coefficient was influenced by TSR only. According to Seo et al [9], the variation of turbine performance in different TSR conditions was directly affected by changes in the angle of attack onto the blade section. Figure 12 shows an angle of attack and the forces on the turbine blade section.…”

“…Based on these procedures, they proposed a new blade design for cavitation inception delay. Seo et al [9] investigated the energy conversion mechanism of a horizontal-axis tidal stream turbine by measuring the near wake flow in a towing tank. An underwater stereo particle image velocimetry (SPIV) system was adopted to measure the wake region.…”