Increased efficiency of hydrokinetic turbines through the use of an obstacle on the channel bottom

Abstract

Nowadays, the growing demand for energy and the current shift towards the eradication of fossil fuels has led to continuous research into and development of alternative clean energies. Among these, one of the least investigated is the extraction of hydrokinetic energy in hydraulic channels. This article highlights an investigation focused on improving the performance of a hydrokinetic turbine installed in a hydraulic channel through the use of an obstacle on the channel bottom, thus providing a solution involving minimum investment and without the need for maintenance. It was found through a series of tests carried out in a hydrodynamic water tunnel that the power produced increases with the height of the obstacle. In addition, a validated numerical model facilitated the completion of the research by studying the influence of the height of the obstacle on the flow rate that passes through the turbine rotor. The latter representing the key factor in the generation of power together with the forces actuating on the blades. Under conditions analogous to those of the literature examples (with the turbine fully submerged), a power increase of about 25% was obtained in the tests.