Hydrodynamics of Atlantic salmon culture tank: Effect of inlet nozzle angle on the velocity field

• Published in: Computers and electronics in agriculture Vol. 158; pp. 79 - 91
• Main Authors: Gorle, J.M.R., Terjesen, B.F., Summerfelt, S.T.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2019; Elsevier BV
• Subjects: Aquaculture; Computational fluid dynamics; Computational Fluid Dynamics (CFD); Culture; Fish; Fluid flow; Hydraulic Retention Time (HRT); Hydrodynamics; Incompressible flow; Inlet nozzle angle; Inlet nozzles; Inlet pipes; Mathematical models; Recirculation Aquaculture System (RAS); Reynolds averaged Navier-Stokes method; Reynolds number; Salmon; Time dependence; Turbulent flow; Velocimetry; Velocity distribution; Velocity measurement; Inlet nozzle angle; Hydrodynamics; Recirculation Aquaculture System (RAS); Hydraulic Retention Time (HRT); Computational Fluid Dynamics (CFD)
• ISSN: 0168-1699; 1872-7107
• DOI: 10.1016/j.compag.2019.01.046

•Hydrodynamics of a RAS tank of 788 m3 size was studied using turbulence modeling.•Flowfield parameters and the effect of hydraulic retention time were presented.•Different nozzle configurations were investigated for global flowfield.•Inclusion of a radial component in the inflow would improve the velocity field. The aquaculture industry is increasingly interested in using larger rearing tanks of near 1000 m3 to achieve production and economic benefits. Higher Reynolds number due to that order of tank size makes the flow fully turbulent. This paper presents a full-scale computational fluid dynamics (CFD) model of an existing culture tank of 788 m3 size was developed, based on time-dependent incompressible unsteady Reynolds averaged Navier-Stokes (URANS) formulation with the realizable k-ε viscous model. The tank has two inlet pipes, placed closed to side walls of the tank. Each pipe has 11 inlet nozzles, which introduce the flow into the tank parallel to the walls. This base case was validated against the experimental velocity measurements using Acoustic Doppler Velocimetry (ADV) at predefined locations across the central vertical plane of the tank. Turbulence characteristics and hence the hydrodynamic performance of the tank are influenced by inflow characteristics. To conclude this, two redesigns were developed and contrasted with the base design for various flow parameters from the viewpoint of the tank's performance. Redesign 1 has the nozzles turned towards the centre by 42°, while Redesign 2 has bottom 5 nozzles directing the flow towards the centre with the rest injecting the flow parallel to the wall. Distribution of turbulence parameters and vortices reveal that the inflow with a radial component improves the mixing and flow uniformity characteristics of the tank. The present study has shown that relatively minor construction changes aided by CFD can result in major changes in the hydrodynamic properties of large culture tanks for Atlantic salmon.