Abstract
Owing to the continuous consumption of fossil fuel and increasing environmental problems, there is an urgent need to develop technologies for the efficient use of clean energy. In this study, a mono-tangent backward-rotating impeller based on tidal current energy utilization is proposed, and its hydrodynamic performance was studied using the computational fluid dynamics method by establishing a hydrodynamic model of the backward-rotating impeller. The influences of the number of blades, impeller aspect ratio (λ), and different flow speeds on the coefficient of power (cp) of the mono-tangent impeller were investigated. The results show that the value of cp of the mono-tangent impeller with four blades is higher than that of the impellers with two, three, five, and six blades. λ has a significant impact on the backward-rotating impeller, with cp of the impeller reaching an optimal value when λ = 0.5 and the flow speed is 1.25–1.5 m/s (with a tip speed ratio of 0.6–0.75).