导流罩外部结构对微水头水轮机水动力性能的影响研究

To study the influence of adding an external fairing structure on the hydrodynamic performance of low-velocity hydraulic turbines，this paper proposes a parabolic external structure to enhance the turbine's power generation efficiency. The computational fluid dynamics （CFD）method and Fluent simulation software were used to conduct a comparative analysis of the turbine's hydrodynamic performance before and after adding the external structure. The results show that adding the external structure significantly improves the stability of the flow field in the turbine's working area. Based on this，the influence of different upper-to-lower axis ratios of the external structure on the flow field characteristics and impeller performance was further investigated. It was found that adding an external structure with an axis ratio of 19∶21 optimized the water flow uniformity，maximized the impeller's power coefficient，and enhanced the turbine's stability and power generation efficiency.