Investigation of flow field and dissolved oxygen concentration distribution in aquaculture tanks based on computational fluid dynamics

This paper investigated flow velocity distribution within aquaculture tanks (17 m×18 m×19 m) under various circulation rates. The model was based on an actual well boat primarily used for farming high-value species, including Atlantic salmon (Salmo salar). A three-dimensional turbulence model and an oxygen transport model, were employed as analytical tools to evaluate the spatial distribution of dissolved oxygen and assess environmental conditions for fish growth. The effects of key factors, such as total oxygen supply, theoretical oxygen consumption, and outlet flow velocity, affecting the distribution of dissolved oxygen concentration in the tank were also analyzed. A 1:15 scaled physical experiment was conducted based on Reynolds similarity. The results indicated that adjusting the inlet pipes position and moderately increasing oxygen supply has significantly positive effects on the uniformity of flow velocity and dissolved oxygen distribution in the tank. Furthermore, the overall dissolved oxygen concentration was linearly related to the difference between oxygen supply and consumption. When the oxygen supply was insufficient, increasing the circulation was beneficial to improve the ability of tanks to maintain dissolved oxygen. This study provides insights for the design of aquaculture tanks and strategies for oxygen supply at different stages of production.