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http://dx.doi.org/10.7837/kosomes.2021.27.1.145

A Study on the Flow Characteristics of a Sleeve-Jointed Adjusting Piece  

Lee, Chang-Yong (Division of Marine Engineering, Mokpo National Maritime University)
Cho, Dae-Hwan (Division of Marine Engineering, Mokpo National Maritime University)
Publication Information
Journal of the Korean Society of Marine Environment & Safety / v.27, no.1, 2021 , pp. 145-152 More about this Journal
Abstract
The purpose of this study was to determine the optimal distances between pipes to minimize the pressure loss and turbulent intensity. This was accomplished by investigating the distances between sleeve-jointed pipes and the flow changes in pipes based on variations in the Reynolds (Re) number when installing adjusting pieces for the pipes. When the thickness tp of the sleeve-jointed piping was fixed at 5 mm and the pipe lengths Lp were 10, 50, 100, and 200 mm, the correlations with the velocity of the sleeve-jointed part, pressure distribution, length of the reattachment point in the recirculation area, and Re number were analyzed. The flow characteristic of the sleeve-jointed part from a laminar to a turbulent flow region was determined by setting the Re range to 200 ≤ Re ≤ 5,000. This was done by utilizing Ansys Fluent 18.1, which is a commercial program. The enlargement and contraction ratios of the sleeve-jointed part were 1.2 and 0.83, respectively, and the turbulent intensity of the sleeve downstream edge and pressure change both increased as the Re number increased while Lp remained constant. The fact that the flow on the sleeve wall surface was disturbed by tp resulted in losses in velocity energy. Therefore, the edge of the sleeve-jointed part was also effected. When Lp was 10 mm or less, the turbulent intensity of the edge part did not change significantly as the Re number increased. The reattachment point in the recirculation area did not appear at Lp of 10 mm or less and was not affected by the vortex. In the case of 3,000 ≤ Re, the reattachment length of the wall surface of the sleeve-jointed part was nearly constant as Lp increased.
Keywords
Adjusting piece; Sleeve joints; Reattachment point length; Turbulent intensity; Velocity distribution; Fully developed flow;
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