Influence of inlet velocity condition on unsteady flow characteristics in piping with a short elbow under a high-Reynolds-number condition

In the design of the Advanced Sodium-cooled Fast Reactor in Japan, the mean velocity of the coolant is approximately 9 m/s in the primary hot leg (H/L) piping, which has a diameter of 1.27 m. The Reynolds number in the H/L piping reaches 4.2 × 107. Furthermore, a short elbow, which has Rc/D = 1.0 (R...

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Autores principales:	Ayako ONO, Masaaki TANAKA, Jun KOBAYASHI, Hideki KAMIDE
Formato:	article
Lenguaje:	EN
Publicado:	The Japan Society of Mechanical Engineers 2017
Materias:	sodium fast reactor flow separation short elbow fiv large diameter piping Mechanical engineering and machinery TJ1-1570
Acceso en línea:	https://doaj.org/article/f465151d536b471c937b836a7b05efe7
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spelling	oai:doaj.org-article:f465151d536b471c937b836a7b05efe72021-11-26T07:00:24ZInfluence of inlet velocity condition on unsteady flow characteristics in piping with a short elbow under a high-Reynolds-number condition2187-974510.1299/mej.16-00217https://doaj.org/article/f465151d536b471c937b836a7b05efe72017-01-01T00:00:00Zhttps://www.jstage.jst.go.jp/article/mej/4/1/4_16-00217/_pdf/-char/enhttps://doaj.org/toc/2187-9745In the design of the Advanced Sodium-cooled Fast Reactor in Japan, the mean velocity of the coolant is approximately 9 m/s in the primary hot leg (H/L) piping, which has a diameter of 1.27 m. The Reynolds number in the H/L piping reaches 4.2 × 107. Furthermore, a short elbow, which has Rc/D = 1.0 (Rc: curvature radius, D: pipe diameter), is used in the H/L piping to achieve a compact plant layout and reduces plant construction costs. In the H/L piping, flow-induced vibration (FIV) is a concern due to the excitation force caused by pressure fluctuation in the short elbow. In a previous study, the relation between flow separation and pressure fluctuations in the short elbow was investigated under the specific inlet condition of a flat velocity profile of time-averaged axial velocity and relatively low velocity fluctuation intensity. However, the inlet velocity condition of the H/L in a reactor may be a highly turbulent non-uniform profile owing to the complex geometry in the reactor vessel (R/V). In this report, the influence of inlet velocity condition on the unsteady velocity characteristics in the short elbow was studied. Although the flow around the inlet of the H/L in the R/V could not be simulated completely, the inlet velocity conditions were controlled by installing a perforated plate, which appropriately plugged the flow holes. Then, controlled flow patterns were established at a position 2D upstream of the elbow inlet. Observed flow structures by particle image velocimetry indicated that the inlet velocity profiles affected a circumferential secondary flow, which then affected an area of flow separation at the elbow. It was also found that the velocity fluctuation at low frequency components observed upstream of the elbow could remain in downstream of the elbow though its intensity was attenuated.Ayako ONOMasaaki TANAKAJun KOBAYASHIHideki KAMIDEThe Japan Society of Mechanical Engineersarticlesodium fast reactorflow separationshort elbowfivlarge diameter pipingMechanical engineering and machineryTJ1-1570ENMechanical Engineering Journal, Vol 4, Iss 1, Pp 16-00217-16-00217 (2017)
institution	DOAJ
collection	DOAJ
language	EN
topic	sodium fast reactor flow separation short elbow fiv large diameter piping Mechanical engineering and machinery TJ1-1570
spellingShingle	sodium fast reactor flow separation short elbow fiv large diameter piping Mechanical engineering and machinery TJ1-1570 Ayako ONO Masaaki TANAKA Jun KOBAYASHI Hideki KAMIDE Influence of inlet velocity condition on unsteady flow characteristics in piping with a short elbow under a high-Reynolds-number condition
description	In the design of the Advanced Sodium-cooled Fast Reactor in Japan, the mean velocity of the coolant is approximately 9 m/s in the primary hot leg (H/L) piping, which has a diameter of 1.27 m. The Reynolds number in the H/L piping reaches 4.2 × 107. Furthermore, a short elbow, which has Rc/D = 1.0 (Rc: curvature radius, D: pipe diameter), is used in the H/L piping to achieve a compact plant layout and reduces plant construction costs. In the H/L piping, flow-induced vibration (FIV) is a concern due to the excitation force caused by pressure fluctuation in the short elbow. In a previous study, the relation between flow separation and pressure fluctuations in the short elbow was investigated under the specific inlet condition of a flat velocity profile of time-averaged axial velocity and relatively low velocity fluctuation intensity. However, the inlet velocity condition of the H/L in a reactor may be a highly turbulent non-uniform profile owing to the complex geometry in the reactor vessel (R/V). In this report, the influence of inlet velocity condition on the unsteady velocity characteristics in the short elbow was studied. Although the flow around the inlet of the H/L in the R/V could not be simulated completely, the inlet velocity conditions were controlled by installing a perforated plate, which appropriately plugged the flow holes. Then, controlled flow patterns were established at a position 2D upstream of the elbow inlet. Observed flow structures by particle image velocimetry indicated that the inlet velocity profiles affected a circumferential secondary flow, which then affected an area of flow separation at the elbow. It was also found that the velocity fluctuation at low frequency components observed upstream of the elbow could remain in downstream of the elbow though its intensity was attenuated.
format	article
author	Ayako ONO Masaaki TANAKA Jun KOBAYASHI Hideki KAMIDE
author_facet	Ayako ONO Masaaki TANAKA Jun KOBAYASHI Hideki KAMIDE
author_sort	Ayako ONO
title	Influence of inlet velocity condition on unsteady flow characteristics in piping with a short elbow under a high-Reynolds-number condition
title_short	Influence of inlet velocity condition on unsteady flow characteristics in piping with a short elbow under a high-Reynolds-number condition
title_full	Influence of inlet velocity condition on unsteady flow characteristics in piping with a short elbow under a high-Reynolds-number condition
title_fullStr	Influence of inlet velocity condition on unsteady flow characteristics in piping with a short elbow under a high-Reynolds-number condition
title_full_unstemmed	Influence of inlet velocity condition on unsteady flow characteristics in piping with a short elbow under a high-Reynolds-number condition
title_sort	influence of inlet velocity condition on unsteady flow characteristics in piping with a short elbow under a high-reynolds-number condition
publisher	The Japan Society of Mechanical Engineers
publishDate	2017
url	https://doaj.org/article/f465151d536b471c937b836a7b05efe7
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Influence of inlet velocity condition on unsteady flow characteristics in piping with a short elbow under a high-Reynolds-number condition

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