Influence of guide vane outlet angle on a low-head pump system using a novel angle-based parameterization approach

In coastal large low-head pump systems, the inlet and outlet angles of guide vanes play a critical role in affecting the hydraulic performance and energy characteristics. A parameterized design method for guide vanes in low-head pump systems is proposed based on the inlet and outlet angles. The improved geometric parameter approach is modified to meet the geometric and hydraulic requirements of guide vane hydrofoils. The method is validated by fitting an existing guide vane and flexibly adjusting angular parameters. Numerical simulations are conducted to examine the influence of outlet angles on hydraulic performance and energy characteristics. The results show that an appropriate outlet angle effectively suppresses entropy production induced by low-velocity recirculation and strong velocity gradients in the outlet conduit. Furthermore, a non-uniform outlet angle design concept is advanced to improve flow uniformity and reduce system energy consumption. The proposed framework provides a systematic and efficient approach for guide vane design and can be extended to other flow-guiding blade configurations in hydraulic machinery.