Effect of Deflectors on the Flow Characteristics of a Square Pipe with a 90° Bend

doi:10.1007/s12204-021-2278-4

Abstract

Abstract: Pipe flow is a classic hydrodynamic issue. Most pipelines contain bends, and bends cause energy loss and distort the flow because of secondary flow. Deflectors are often used to adjust the flow quality in a bend. In this study, a numerical simulation using ANSYS Fluent 19.0 is used to analyze the effects of the deflector number, location and angle on the flow characteristics of a square pipe with a 90° bend. The velocity non-uniformity and the head loss are analyzed quantitatively. The secondary flow is presented visually, and its evolution characteristics are assessed. An optimized installation scheme for the deflectors is discussed, and a reference is provided for controlling the flow quality in bends via deflectors.

Key words: bend| deflector| head loss| secondary flow

摘要： Pipe flow is a classic hydrodynamic issue. Most pipelines contain bends, and bends cause energy loss and distort the flow because of secondary flow. Deflectors are often used to adjust the flow quality in a bend. In this study, a numerical simulation using ANSYS Fluent 19.0 is used to analyze the effects of the deflector number, location and angle on the flow characteristics of a square pipe with a 90° bend. The velocity non-uniformity and the head loss are analyzed quantitatively. The secondary flow is presented visually, and its evolution characteristics are assessed. An optimized installation scheme for the deflectors is discussed, and a reference is provided for controlling the flow quality in bends via deflectors.

关键词: bend| deflector| head loss| secondary flow

CLC Number:

O 352

JIANG Chenqi (江晨琦), GONG Zhaoxin (宫兆新) . Effect of Deflectors on the Flow Characteristics of a Square Pipe with a 90° Bend[J]. J Shanghai Jiaotong Univ Sci, 2021, 26(2): 163-169.

References 14

[1]	GONTSOV N G, MARINOVA O A, TANANAEV A V. Turbulent flow around a bend in a circular pipe [J].Hydrotechnical Construction, 1984, 18(12): 596-602.
[2]	DUTTA P, NANDI N. Numerical study on turbulent separation reattachment flow in pipe bends with different small curvature ratio [J]. Journal of the Institution of Engineers (India): Series C, 2019, 100(6):995-1004.
[3]	XIE H Y. Numerical simulation of local water pressure loss for bend pipe of circular section at 90 degrees [J].Journal of Water Resources and Water Engineering,2014, 25(5): 190-192 (in Chinese).
[4]	WEI Z Y. Numerical simulation of resistance loss and flow field characteristics of bend [J]. Gansu Water Resources and Hydropower Technology, 2018, 54(6): 34-36 (in Chinese).
[5]	LUO Y H, YANG J, PAN W M. Calculation of turbulent flow in 90? elbow pipe with square cross-section[J]. Engineering Journal of Wuhan University, 2003,36(2): 62-65 (in Chinese).
[6]	QIU L J, ZHANG G F, HAO M. Numerical simulation of internal flow field in bend duct based on FLUENT[J]. Journal of Liaoning Shihua University, 2013,33(1): 48-52 (in Chinese).
[7]	SUN Y Z, HU S G, ZHAO J, et al. Numerical study on flow characteristics of 90° bend pipe under different Reynolds number [J]. Journal of University of Shanghai for Science and Technology, 2010, 32(6): 525-529(in Chinese).
[8]	DUTTA P, SAHA S K, NANDI N, et al. Numerical study on flow separation in 90? pipe bend under high Reynolds number by k-ε modelling [J]. Engineering Science and Technology, an International Journal,2016, 19(2): 904-910.
[9]	HUMPHREY J A C, WHITELAW J H, YEE G. Turbulent flow in a square duct with strong curvature [J].Journal of Fluid Mechanics, 1981, 103: 443-463.
[10]	DING Z R. Engineering fluid mechanics (Volume 1)[M]. Beijing: Mechanical Industry Press, 2013 (in Chinese).
[11]	WANG Z J, LI X H, TANG L J, et al. Optimization research on deflectors installed in right-angle bend tube with rectangular section [J]. Huadian Technology,2019, 41(8): 32-37 (in Chinese).
[12]	LAN L W. Numerical simulation analysis of inducting elbow [J]. Guangzhou Chemical Industry, 2014, 42(1):105-106 (in Chinese).
[13]	YU F, LIU M, LI W D, et al. Layout optimization of guide plates in a 90 degree elbow with rectangular cross section [J]. Journal of Chinese Society of Power Engineering, 2015, 35(2): 147-152 (in Chinese).
[14]	LIU F, HE J Y, LONG Z H. Parameter sensitivity analysis of water head loss calculation of 90° curved pipe based on CFD [J]. Journal of Irrigation and Drainage, 2019, 38(8): 79-83 (in Chinese).

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[15]	Lan LI, Yin-na ZHANG. Design of Static Bend Stiffener for Flexible Pipes [J]. Ocean Engineering Equipment and Technology, 2014, 1(3): 223-226.