Investigation the Structural Scale of Diameter-to-Depth Ratio on the Hydrodynamics in Recirculating Aquaculture System

Abstract

To maximize the spatial utilization rate of the recirculating aquaculture system (RAS) and improve the growth conditions of aquaculture varieties, the present study used the numerical simulation method to investigate the distribution characteristics of the flow velocity inside the aquaculture tank. It is of great practical importance for the design and optimization of the aquaculture tank structures. The computational fluid dynamics (CFD) method and the RNG k-ε turbulent model were applied to analyze the effects of diameter-to-depth ratio (L/H) on the hydrodynamic characteristics inside the aquaculture tank, including the average flow velocity, resistance coefficient, flow velocity uniformity, energy utilization coefficient and vortex. The simulated results were verified with the experimental results to prove the effectiveness of the method. The results show that as the diameter-to-depth ratio (L/H) of the rectangular arc angle aquaculture tank increases, the turbulence intensity in the flow field gradually weakens, the low-velocity area increases, and the average flow velocity decreases. When the diameter-to-depth ratio (L/H) is 3:1-5:1, uniformity coefficients, energy effective use coefficients, and Fraud correction coefficients have significantly improved, and the flow pattern in the aquaculture tank is the best. Through the research of the present study, it can effectively improve the effectiveness of the use of aquaculture tank space, and provide technical support for the realization of the welfare aquaculture of the recirculating aquaculture system.

Keywords: Recirculating aquaculture system, Diameter-to-depth ratio, Computational fluid dynamics, Flow field, Energy utilization coefficient