In order to solve the technical bottlenecks of low efficiency and high starting flow velocity of traditional turbines in the area of development of micro-head hydropower resources, a new type of hydraulic turbine in which the dual-duct is used was suggested and was structurally optimized to enhance the energy conversion efficiency and operational stability of micro-head hydraulic turbines. By integrating Computational Fluid Dynamics with orthogonal experimental design, the influence of blade inlet angle, blade count, and axial length on the flow field within the turbine and hydraulic performance of the turbine was analyzed systematically, which gave the best runner set-up. Based on vortex analysis, supporting plate-type flow guide ribs were added at the diffuser exit to optimize the vortex structure. The results show that the optimized turbine output increased from 3.38 kW to 3.72 kW with a 10.06% increase, and the efficiency improved to 75.05% with a 18.41% enhancement. In addition, there is a significant wake vortex structure at the outlet of the micro-head dual-duct hydraulic turbine, and the asymmetric layout of three runner blades can achieve better vortex breaking and dissipation effects, improving flow field stability and unit operation reliability. The use of a dual-duct diffuser for micro-head hydropower provides a new technological path for promoting efficient development of micro-head hydraulic resources.
Zhou et al. (Thu,) studied this question.