The Effect of Diameter on Multistage Deep Water Jet Turbine Aerator Performance Using Computational Fluid Dynamics

Abstract This study focuses on the development of a Multistage Deep Water Jet Turbine Aerator (MDWJTA), which is designed to improve dissolved oxygen distribution at the bottom of aquaculture ponds. A three-dimensional Computational Fluid Dynamics (CFD) model was utilized to simulate the aerator’s performance under transient conditions. This model, which incorporated a k-ω turbulence model and an Eulerian multiphase approach, tested four different impeller diameters: 22, 24, 26, and 28 cm, all operating at 400 rpm. The novelty of this research lies in its systematic evaluation of how multi-stage blade diameter affects both flow turbulence and oxygen transfer efficiency. The results show that impeller size significantly impacts mixing and aeration performance. For instance, the 22 cm impeller produced a peak velocity of 6.3 × 10 4 m s −1 but provided limited vertical mixing. Conversely, the 28 cm impeller generated excessive turbulence and undesirable bubble clustering. The 26 cm diameter impeller achieved the most balanced performance. It produced a stable velocity field (3.2 × 10 2 m s −1 ), uniform air fraction dispersion (6.5 × 10 −4 ), and the widest oxygen mass distribution (1.17 × 10 −5 kg s −1 ). These findings confirm that optimizing impeller size is crucial for maximizing aeration efficiency and provide practical guidance for designing more energy-efficient aerators for aquaculture systems.