Effect mechanism of inlet elbow on energy consumption of large low-head pumping system and its optimization design

• DOI: 10.1063/5.0242524
• Publication Date: 2025-01-02T14:53:17Z
• Authors: Tianxu Yan; Baoyun Qiu; Jianping Yuan

To investigate the effect of inlet elbow geometry on the performance of a large low-head pumping system and improve its comprehensive performance, this paper calculated and analyzed the internal flow fields, external characteristics, and entropy production distribution of the pumping system with different parametric combinations of the inlet elbow via numerical simulations with a Reynolds averaged Navier Stokes-volume of fluids fixed net head method. The energy characteristics were further studied using a newly introduced method of local internal energy change to visualize energy consumption. An automatic multi-software optimization design method was developed based on MATLAB, a feed-forward neural network, and a differential evolution algorithm to optimize the geometrical parameters of the inlet elbow. The research results indicate that appropriate heights of the throat and truncated cone improve velocity distribution, decrease the hydraulic loss in the inlet conduit, and foster a favorable flow condition at the pump inlet and outlet. Well-distributed axial velocity at the impeller inlet improves the pump efficiency. Well-distributed axial velocity and circulation at the pump outlet could reduce and eliminate flow separation, reflow, and vortices in the outlet conduit, thereby reducing energy consumption. Compared with the original design, the optimized geometry of the inlet elbow significantly improves the pumping system efficiency by 8.4 percentage points. The findings reveal the effect of the inlet elbow geometry on the performance of large low-head pumping systems and provide an easy, efficient, and economical method for the design and modification of low-head pumping systems.