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http://dx.doi.org/10.5762/KAIS.2016.17.10.618

A Study on Velocity Distribution Characteristics for Each Location and Effectiveness of Straight Duct Length in a Square-sectional 180° Bended Duct  

Chen, Jing-Jing (Dept. of Mechanical Engineering, Graduate School, Gachon Univ.)
Yoon, Jun-Kyu (Dept. of Mechanical Engineering, Gachon Univ.)
Publication Information
Journal of the Korea Academia-Industrial cooperation Society / v.17, no.10, 2016 , pp. 618-627 More about this Journal
Abstract
This study numerically analyzes the characteristics of the velocity distribution for each location of a square-sectional $180^{\circ}$ bent duct using a Reynolds Stress Turbulent model. The flow parameters were varied, including the working fluids, inlet velocity, surface roughness, radius of curvature, and hydraulic diameter. The boundary conditions for computational fluid dynamics analysis were inlet temperatures of air and water of 288 K and 293 K, inlet air velocity of 3-15 m/s, inner surface roughness of 0-0.001 mm, radius of curvature of 2.5-4.5 D, and hydraulic diameter of 70-100 mm. The working fluid characteristics were highly affected by changes in the viscous force. The maximum velocity profiles in the bent duct were indicated when the $90^{\circ}$ section was in the region of X/D=0.8 and the $180^{\circ}$ section was in the region of Y/D=0.8. Lower surface roughness and higher radius of curvature resulted in a higher rate of velocity change. Also, an efficient measuring location downstream of the bent duct is suggested since the flow deviations were the most stable when the straight duct length was in the region of L/D=30. The minimum deviations at the same velocity conditions according to the hydraulic diameter were mostly indicated in the range of L/D=15-30 based on the standard deviation characteristics.
Keywords
Square-sectional Bended Duct; Reynolds Stress Model; Velocity Distribution; Working Fluids; Straight Duct Length;
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Times Cited By KSCI : 5  (Citation Analysis)
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