Experimental and numerical investigation of a three-blade horizontal axis hydrokinetic water turbine (HAHWT) in high blockage conditions

Horizontal-axis hydrokinetic water turbines (HAHWT) represent a cost-effective and low-maintenance opportunity for hydropower generation in low-velocity channels. To enhance understanding of the potentiality of an original HAHWT prototype working at high blockage operations (e.g. tidal channels, man-made water infrastructure, offshore energy platforms), an experimental and numerical investigation was carried out to assess its performance curves under sub-critical flow conditions. The dependence of the turbine efficiency on the Froude Number (Fr), Reynolds Number (Re) and Blockage Ratio (Br) was thus investigated, showing their relevance for the overall turbine assessment. The overall energy exploitation was strictly dependent on the contribution of the potential head, thus showing the significant reduction of the turbine efficiency for partially submerged operations.