Numerical and experimental performance analysis of a horizontal axis hydrokinetic turbine

Abstract

Alternative technologies such as hydrokinetic turbines can improve the electric energy conditions in rural or non interconnected areas with a low environmental impact. However, as they are an emergent device they must be studied further to better understand their phenomenology a nd the ways to improve their performance. The numerical and experimental evaluation of rotors under specific operation conditions depending on their hydrodynamic profiles result in efficiency curves for evaluated prototypes, so that devices are proposed which take full advantage of the flow conditions of a specific place. Considering the above, the main objective of this work was to numerically and experimentally evaluate a horizontal axis hydrokinetic turbine rotor prototype with an EPPLER E817 hydrodyna mic profile for a flow velocity of 1.4 m s 1 The simulations were carried out by means of computational fluid dynamics; the k ? SST turbulence model was used, and the torque was monitored. Then, the Grid Convergence Index ( was calculated to establish the results’ numerical uncertainty. For experimentation, the rotor was additively manufactured and tested in a test bench, where tests at velocity of nearly 1,4 m s 1 were performed and the braking voltage was varied to  measure torque at different tip speed ratio (TSR Finally, the experimental and numerical curves of power coefficient ( versus TSR were compared Both the simulation and experimental results show th at a TSR of about 4 represents the best operating conditions, but, due to mechanical losses in the experimental setup, the reported Cp values differ between a numerical 0.4 34 and an experimental 0.2 67 The power generated by the evaluated rotor could achie ve 117.0 W, thus showing the potential of this technology for electrical power supply with low environmental impact.