Flows in T-Junction Piping System (1st Report, Flow Characteristics and Vortex Street Formed by Branch Pipe Flow)

Hibara, Hideki; Muramatsu, Toshiharu; Hirata, Naoki; Sudo, Kozo

doi:10.1299/kikaib.70.1192

Cited by 11 publications

(8 citation statements)

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“…The wall shear stress ( w is evaluated by using u ( in Eq. (22). The wall shear stress ( w is decomposed into components in the Cartesian coordinate system by using the unit vector of Eq.…”

Section: Large Eddy Simulation Approachmentioning

confidence: 99%

“…As for the existence of such a large-scale vortex structure, Hibara et al, 22) successfully visualized the hairpin vortex structure generated in the T-pipe water experiment at laminar flow conditions and Sau and Mahesh 23) predicted the hairpin vortex structure in their study of the jet in cross flow at low Reynolds number condition (Re b < 600) by using the direct numerical simulation. At high Reynolds number conditions Re m ¼ 1:06 Â 10 5 and Re b ¼ 2:1 Â 10 4 , Tanaka et al…”

Section: Large-scale Vortex Structure In Mixing Processmentioning

confidence: 99%

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Thermal Mixing in T-Junction Piping System Related to High-Cycle Thermal Fatigue in Structure

Tanaka

Ohshima

Monji

2010

Journal of Nuclear Science and Technology

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The numerical simulation code ''MUGTHES'' has been developed by the authors to investigate thermal striping phenomena caused by turbulence mixing of fluids at different temperatures and to utilize with an evaluation method for high-cycle thermal fatigue. MUGTHES employs the large eddy simulation (LES) approach to predict unsteady thermal mixing phenomena and the boundary fitted coordinate (BFC) system to fit complex boundary shapes in a reactor. In this paper, thermal striping phenomena in a T-junction piping system (T-pipe) are numerically simulated as a code validation study and the simulation results are used to investigate temperature fluctuation generation mechanism in the T-pipe. The boundary conditions for the simulation are chosen from the WATLON experiment which was a water experiment conducted at JAEA using the T-pipe. In the simulation, the standard Smagorinsky model is employed as a turbulence eddy viscosity model with the model coefficient of 0.14 (¼ Cs). Numerical results of MUGTHES are compared with experimental velocity and temperature profiles. Applicability of MUGTHES to the thermal striping phenomena is confirmed through the numerical simulation in the T-pipe and the characteristic large-scale vortex structure which dominates thermal mixing and may cause high-cycle thermal fatigue is revealed.

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“…The wall shear stress ( w is evaluated by using u ( in Eq. (22). The wall shear stress ( w is decomposed into components in the Cartesian coordinate system by using the unit vector of Eq.…”

Section: Large Eddy Simulation Approachmentioning

confidence: 99%

Section: Large-scale Vortex Structure In Mixing Processmentioning

confidence: 99%

Thermal Mixing in T-Junction Piping System Related to High-Cycle Thermal Fatigue in Structure

Tanaka

Ohshima

Monji

2010

Journal of Nuclear Science and Technology

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“…Additionally, it was recognized that the hairpin vortex structure provided cold fluid to the wake in accordance with its rotating motion (Tanaka, 2009b). As for such large-scale vortex structures, Hibara et al (2004) successfully visualized the hairpin vortex structures generated in the T-pipe water experiment at laminar flow conditions and Sau and Mahesh (2007) predicted the hairpin vortex structure in the jet in cross flow at low Reynolds number condition (Re b <600) by using the direct numerical simulation. Tanaka et al (2004) indicated hairpin vortex structure existence in the T-pipe with elbow pipe in upstream side by the numerical simulation at high Reynolds number conditions of Re m =1.1x10 5 and Re b =2.1x10 4 .…”

Section: Mixing Phenomena In the T-pipementioning

confidence: 95%

Numerical Simulations of Thermal-Mixing in T-Junction Piping System Using Large Eddy Simulation Approach

Tanaka

Murakami

Miyake

et al. 2011

ASME-JSME-KSME 2011 Joint Fluids Engineering Conference: Volume 1, Symposia – Parts A, B, C, and D

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A numerical simulation code MUGTHES has been developed by the authors to investigate thermal striping phenomena related to high-cycle thermal fatigue in structure. The MUGTHES employs the large eddy simulation (LES) approach to predict unsteady thermal mixing phenomena and the boundary fitted coordinate system to fit complex boundary shapes in a reactor. In this paper, a part of the verification and validation (V&V) study of the MUGTHES is introduced and numerical simulations of a T-junction piping system (T-pipe) are described. The V&V examinations are conducted with fundamental problems in literatures with a concept of the phenomena identification ranking table (PIRT). After the V&V examinations, thermal striping phenomena in a T-pipe are numerically investigated by the MUGTHES with the LES approach. As for the boundary conditions, two typical flow patterns of a wall jet and an impinging jet conditions are chosen from the WATLON experiment which is a water experiment at the JAEA using a T-pipe. The numerical results are validated by comparing with measured velocity and temperature profiles. Characteristic large-scale vortex structures are identified around the branch pipe jet in the mixing process. The generation mechanism of temperature fluctuation in the T-pipe is revealed in relation with the large-scale vortex structures.

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“…Separated flows formed at the corners make vortex or low-speed regions near the junction corners, and these regions reduce the effective cross sectional area of pipe 3 and cause a large flow resistance. The flow characteristics and heat convection characteristics have been investigated by some researchers such as Asano et al (Asano et al, 2005), Hibara et al (Hibara et al, 2004), (Hibara et al, 2005), Nakayama et al (Nakayama et al, 2006), and Ito et al (Ito et al, 2005).…”

Section: Received 2 April 2014mentioning

confidence: 99%

Effects of flow rate ratio on loss reduction of T-junction pipe

Ando

Shakouchi

Takamura

et al. 2014

JFST

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T-junction pipes are frequently used in industrial facilities to split one flow into two flows or to merge two flows into one flow. In the counter-flow type of confluence in this type of pipe, separated vortex flow regions are formed near the junction corners and these regions cause a large flow resistance. The corners of a T-junction pipe are generally made round to avoid flow separation and to reduce the flow resistance or loss, but this method requires a junction corner removal process. In this study, we mount small weir-shaped obstacles on the walls of pipes upstream of the junction corner to reduce the loss. We examine the effect of the flow rate ratio on the loss and clarify the obstacle height and position conditions that reduce the loss for a wide range of flow rate ratio.

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Flows in T-Junction Piping System (1st Report, Flow Characteristics and Vortex Street Formed by Branch Pipe Flow)

Cited by 11 publications

References 0 publications

Thermal Mixing in T-Junction Piping System Related to High-Cycle Thermal Fatigue in Structure

Thermal Mixing in T-Junction Piping System Related to High-Cycle Thermal Fatigue in Structure

Numerical Simulations of Thermal-Mixing in T-Junction Piping System Using Large Eddy Simulation Approach

Effects of flow rate ratio on loss reduction of T-junction pipe

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