Document Type : Original Article
Abstract
In recirculating aquaculture systems, inlet flow current usually enters from the inner pyramid of the tank in the form of submerged jets. The hydraulics of jet alignment has an important effect on flow uniformity and solid removal efficiency. This paper examined experimental analysis of flow pattern in a cylindrical tank by placing a nozzles at each of three depths using four angle options (20°, 40°, 60°, and 80°) between the radius and jet alignments. The results indicate that angles of 40° and 60° created more uniform current in the tank. Changing the jet alignment from 20° to 80° decreased the number of local eddies and increased the average velocity in the tank. Comparison of inlet currents from one nozzle and from three nozzles showed that increasing the number of nozzles increased the jet velocity and the average velocity in the tank, but decreased the ratio of average velocity of the tank to external velocity of the nozzle jet. Paired comparisons of four options (average velocity for angles of 20° (op. 1), 40° (op. 2), 60° (op. 3), and 80° (op. 4)) show that options 2 and 3 had the strongest correlation. Shear stress monitoring in a round tank showed that shear stress increased at the stations of options 2 and 4. Increasing the ratio of h/H, increased the Froude number near the bed of the tank.
Keywords
59, 13-22.
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