Impacts of jet inflow on hydrodynamic performance and waste removal efficiency in recirculating aquaculture system aquaculture tanks based on prototype experiments

Although scaled physical models and numerical simulations have been employed to study the hydrodynamic performance of recirculating aquaculture system (RAS) aquaculture tanks, there remains a paucity of prototype experiments that fully reflect the actual hydrodynamic performance. In this study, a prototype experiment was conducted on RAS aquaculture tanks, utilizing advanced image processing techniques specifically adapted to the prototype scale. This study focused on impacts of various jet inflow parameters, including jet inflow angle (0°, 10°, 20°, 30°, 40°, 45°, 50°, 60°, and 70°), jet inflow rate (150, 180, 210, and 240 l·min−1), jet inflow area (942 and 1884 mm2), and jet inflow location (curved wall and straight wall), on the hydrodynamic performance and waste removal efficiency of RAS aquaculture tanks. The results demonstrated the hydrodynamic performance—specifically average flow velocity, flow field uniformity, and the extent of low-velocity zones conjointly determining waste removal efficiency. The curved wall proved to be the optimal location for inflow pipe placement, while a 45° jet angle yielded the best balance between hydrodynamic performance optimization and waste removal efficiency. Furthermore, reducing the inlet area significantly improved average flow velocity and flow uniformity, whereas variations in inlet flow rate had minimal impact on these factors. Supported by these compelling findings, this study offers theoretical insight and practical guidance for achieving efficient aquaculture in RAS, thereby contributing to the advancement of sustainable aquaculture practices.