Experimental &amp; Computational Fluid Dynamics Study of the Suitability of Different Solid Feed Pellets for Aquaculture Systems

Štěpán Papáček,Mohammadmehdi Saberioon,Karel Petera,Vlastimil Stejskal,Petr Císař

doi:10.3390/app10196954

Abstract

Fish feed delivery is one of the challenges which fish farmers encounter daily. The main aim of the feeding process is to ensure that every fish is provided with sufficient feed to maintain desired growth rates. The properties of fish feed pellet, such as water stability, degree of swelling or floating time, are critical traits impacting feed delivery. Some considerable effort is currently being made with regard to the replacement of fish meal and fish oil with other sustainable alternative raw materials (i.e., plant or insect-based) with different properties. The main aim of this study is to investigate the motion and residence time distribution (RTD) of two types of solid feed pellets with different properties in a cylindrical fish tank. After experimental identification of material and geometrical properties of both types of pellets, a detailed 3D computational fluid dynamics (CFD) study for each type of pellets is performed. The mean residence time of pellets injected at the surface of the fish tank can differ by up to 75% depending on the position of the injection. The smallest residence time is when the position is located at the center of the liquid surface (17 s); the largest is near the edge of the tank (75 s). The maximum difference between the two studied types of pellets is 25% and it increases with positions closer to the center of the tank. The maximum difference for positions along the perimeter at 3/4 tank radius is 8%; the largest residence times are observed at the opposite side of the water inlet. Based on this study, we argue that the suitability of different solid feed pellets for aquaculture systems with specific fish can be determined, and eventually the pellet composition (formula) as well as the injection position can be optimized.

Highlights

Modern aquaculture starts to be more reliable upon using recirculating aquaculture systems (RAS)as an effective way to produce large quantities of fish using small footprints for building [1]
The computational fluid dynamics (CFD) simulations done in this work illustrate the impact of various parameters on the mean residence time of feed pellets in a cylindrical fish tank (Figure 1), which might be quite significant concerning the sustainability of such aquaculture systems
Knowing that the quantitative results depend on both (i) the specific design and operating conditions of the fish tank and (ii) feed pellets properties, we present some of them

Summary

Introduction

Modern aquaculture starts to be more reliable upon using recirculating aquaculture systems (RAS)as an effective way to produce large quantities of fish using small footprints for building [1]. Modern aquaculture starts to be more reliable upon using recirculating aquaculture systems (RAS). The rule of thumb in such intensive systems is to remove solid particles or uneaten food as soon as possible. In-tank solid particle separation by devices as a dual drain and particle traps, Appl. Sci. 2020, 10, 6954 or next to tank devices based on sedimentation are used [2,3]. Such devices involve vortex separators, radial flow vortex or lamellar settlers as a solution for particle removal including uneaten feed [4]

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