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TECHNICAL PAPERS

Resistance and Fluctuating Pressures of a Large Elbow in High Reynolds Numbers

[+] Author and Article Information
Tadashi Shiraishi

Thermal System Laboratory, Takasago R&D Center, Mitsubishi Heavy Industries Ltd., 2-1-1 Shinhama, Arai-cho, Takasago-shi, Hyogo, 676-8686, Japantadashi_shiraishi@mhi.co.jp

Hisato Watakabe

Thermal System Laboratory, Takasago R&D Center, Mitsubishi Heavy Industries Ltd., 2-1-1 Shinhama, Arai-cho, Takasago-shi, Hyogo, 676-8686, Japan

Hiromi Sago

Advanced Nuclear Plant Designing Section, Nuclear Plant Designing Department, Kobe Shipyard & Machinery Works, Mitsubishi Heavy Industries Ltd., 1-1, Wadasaki-cho 1-chome, Hyogo-ku, Kobe-shi, Hyogo, 652-8585, Japanhiromi_sago@mhi.co.jp

Mamoru Konomura

Advanced Nuclear System Research and Development Directorate, Japan Atomic Energy Agency, 4002 Narita-cho, Oarai, Ibaraki, 311-1393, Japankonomura.mamoru@jaea.go.jp

Akira Yamaguchi

Quantum and Energy Engineering, Division of Sustainable Energy and Environment Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japanyamaguchi@nucl.eng.osaka-u.ac.jp

Tadashi Fujii

FBR System Design Group, FBR System Engineering Unit, Advanced Nuclear System Research and Development Directorate, Japan Atomic Energy Agency, 4002 Narita-cho, Oarai, Ibaraki, 311-1393, Japanfujii.tadashi@jaea.go.jp

J. Fluids Eng 128(5), 1063-1073 (Feb 15, 2006) (11 pages) doi:10.1115/1.2236126 History: Received March 08, 2005; Revised February 15, 2006

For the Japan Atomic Energy Agency sodium-cooled fast reactor, an experimental study on the fluctuating pressure of the hot legs was carried out with tests in a 1/3-scale model. The total resistance coefficient is consistent with published data, and, additionally, our research has given data up to the Reynolds number of 8.0×106. The flow visualization and velocity measurement confirmed the independence of the flow on the Reynolds number. Pressures on the pipe wall were statistically examined to predict the characteristics of fluctuating pressures of the hot legs. It reveals that generation of fluctuating pressure is dominant on the boundary of flow separation and reattachment.

Copyright © 2006 by American Society of Mechanical Engineers
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References

Figures

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Figure 1

The configuration of the primary cooling system of the JSFR. NsL is the nominal sodium level in the reactor vessel.

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Figure 2

Schematic of the test facility. 350A, 500A, and 600A are 14B, 20B, and 24B of pipes, respectively.

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Figure 3

1/3-scale model pipe installed on the top of the rectifying tank (inner diameter=412.7mm)

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Figure 4

1/3-scale model of the hot leg with pressure transducers. Velocity distributions were measured in Sections I-IV by laser Doppler velocimeter. Dimensionless radius is r*=r∕D, where r is a radius and D the diameter of the pipe. Totally 124 pressure transducers are flush-mounted on the inner wall of the pipe; 12 at locations B, C, D, E, F, H, and K, 6 at A, 11 at B′ and C′, 2 at G, I, J, and L, and 1 at A′, A″, K′, and K″.

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Figure 5

Total resistance coefficient: (a) published data of a bend after Idelchik (2), (b) converted data from (a) for the hot-leg dimension, (c) present data of 1/3-scale hot leg model, (d) resistance coefficient of elbow only from (c), and (e) extrapolation using Colebrook and White’s formula (3)

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Figure 6

Flow pattern in the model pipe for mean velocity of 9.2m∕s at room temperature

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Figure 7

Dimensionless velocity distributions in Sections I-IV at room temperature. The open symbols indicate axial velocity components, and the solid symbols circumferential ones.

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Figure 8

Local velocities in the elbow for mean velocity of 9.18m∕s at room temperature, which is slightly slower than 9.28m∕s for quantitative measurement. Velocities are measured using pictures of injected bubbles taken by a high-speed camera with a small time interval. The deviation due to the refraction of the acrylic-resin wall is compensated. The frame rate is 4500frames∕second and migration lengths of bubbles are about 10 to 60mm.

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Figure 9

Fluctuating pressures at the circumferential angle of 180deg for mean velocity of 9.28m∕s at room temperature

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Figure 10

Power spectra of fluctuating pressures at the circumferential angles of 0 and 180deg for mean velocity of 9.28m∕s at room temperature

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Figure 11

Power spectra at the circumferential angles of 150 and 210deg compared with that at 180deg near the boundary of separation in Section D for mean velocity of 9.28m∕s at room temperature

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Figure 12

Cross-correlation factor of fluctuating pressure at the circumferential angles of 150 and 210deg in section D for mean velocity of 9.28m∕s at room temperature

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Figure 13

Probability densities of fluctuating pressure at the circumferential angle of 180deg for mean velocity of 9.28m∕s at room temperature. The coordinates are self-adjustable scales in order to indicate negative pressure spikes and to compare the shapes of the probability densities each area of which is one.

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Figure 14

Probability densities near the boundary of separation in Section D for mean velocity of 9.28m∕s at room temperature

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Figure 15

Dependency of fluctuating pressures on the Reynolds number

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Figure 16

Dependency of fluctuating pressures on flow velocity

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Figure 17

Distribution of intensity, skewness, and kurtosis of fluctuating pressures

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