In response to the issues of fish injury and low working efficiency during the operation of vacuum fish pump (VFP) , improvements were made to the process flow and internal structure of the vacuum tanks, leading to the development of a new type of fish pump, the flow-guiding fish pump (FGFP) . The vacuum tank of the FGFP is placed vertically, with the fish intake pipe passing through the bottom of the vacuum tank and entering the interior. The top of the fish inlet pipe featured an inverted trumpet-shaped diversion structure . During the capture process, under the suction of the centrifugal pump, the fish and water mixture enters the vacuum tank, with the fish remaining inside the tank and the water being discharged. Through theoretical calculation, the catching efficiency of the FGFP and the VFP was compared, and the comparative analysis of the numerical simulation results of the FGFP and the VFP were carried out by the computational fluid dynamics method. A prototype of the FGFP was created and its performance experiment was carried out. The study found that, using the data with a fish-to-water ratio of 1:1 in the water pool and the vacuum tank as a benchmark, when the fish-to-water ratios in the water pool were 1:2, 1:3, 1:4, and 1:5, the FGFP took 20.4%, 30.6%, 36.8%, and 40.8% less time to transport the same mass of fish compared to the VFP. During the capture process, t here was a large rang e of strong vortex in the vacuum tank of the VFP , which can easily cause fish injuries. In contrast, the vacuum tank of the FGFP has less noticeable vortices, making it more fish-friendly and significantly reducing the probability of fish injury. The conveying capacity of the FGFP does not change with the height of the fish. These research results can provide theoretical basis and references for the design of the FGFP.
Keywords: flow-guiding fish pump ; fish injury; c apture efficiency; f low-guiding structure; numerical simulation; performance experiment