Pump station engineering is extensively utilized in water supply and drainage, as well as agricultural irrigation. Due to its geographical advantages and significant comprehensive benefits, the construction of pumping stations in coastal areas has gained substantial attention in recent years. Adverse flow conditions caused by various factors negatively affect the inlet flow regime of pumps, becoming a key factor that restricts the operating life and further development of pump station systems. Optimizing the flow regime in the forebay is crucial for enhancing overall engineering quality, minimizing pump performance degradation, and reducing the risks of cavitation and vibration. This study investigates the flow characteristics of the forebay by combining the Navier–Stokes equations and the $k-\epsilon$ RNG turbulence model. The analysis focuses on the internal flow field, transverse flow before the inlet channel, and the uniformity of flow velocity distribution after the inlet channel. Numerical simulations are validated through physical model tests. We examine the flow characteristics in the forebay, analyze the causes of internal flow disorder, and propose a reasonable and practical rectification scheme for the forebay. Additionally, we elucidate the mechanism of flow state optimization through partition walls. The findings indicate that with the optimal partition wall length, the average elimination rate of transverse flow velocity before the pump station inlet channel reached 48.3%, and the uniformity of flow velocity distribution after the inlet increased by 3.24%. These research findings contribute to mitigating cavitation and vibration in water pump units, providing theoretical support for the safe operation of coastal pumping stations.

As a crucial component of water conservancy infrastructure and a core element of power equipment, the stability and reliability of the intake structure in large axial-flow pump systems (AFPS) play a pivotal role in ensuring the safety of water resource allocation projects, agricultural irrigation systems, and flood control and disaster mitigation efforts. Gaining a comprehensive understanding of the mechanisms underlying velocity distortion within the intake system, particularly the evolution of vortex patterns, is vital for mitigating hydraulic transient risks, improving flow structure stability, and preventing catastrophic failures in pump station engineering. This study systematically examines the instability mechanisms of the intake system caused by wall-attached vortices during the operation of AFPS, with an emphasis on flow uniformity, vortex position identification, and the extent of velocity distortion. Transient flow processes and velocity distributions in a large axial-flow pump system were numerically simulated using a three-dimensional volume of fluid + Level Set method to model intake flows at the pump system. The numerical simulation outcomes were validated against experimental data obtained from a model pump system. The spatiotemporal evolution of vortices was analyzed through advanced visualization techniques, and the instability phenomena induced by these vortices were assessed using velocity distribution uniformity tests and entropy production theory. Furthermore, key correlation factors influencing vortex generation and velocity distortion were identified, leading to the development of proactive strategies aimed at enhancing the safety and stability of the intake system.