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Journal Articles

Local gas-liquid two-phase flow characteristics in rod bundle geometry

Xiao, Y.*; Shen, X.*; Miwa, Shuichiro*; Sun, Haomin; Hibiki, Takashi*

Konsoryu Shimpojiumu 2018 Koen Rombunshu (Internet), 2 Pages, 2018/08

In order to develop constitutive equations of two-fluid model in rod bundle flow channels, experiments of adiabatic air-water upward two-phase flow in 6$$times$$6 rod bundle flow channel were performed. Local flow parameters such as void fraction, interfacial area concentration (IAC) and so on were measured by a double-sensor optical probe. The area-averaged void fraction and IAC data were compared with the predictions from a drift-flux model and an IAC correlation.

Journal Articles

Some characteristics of gas-liquid two-phase flow in vertical large-diameter channels

Shen, X.*; Schlegel, J. P.*; Hibiki, Takashi*; Nakamura, Hideo

Nuclear Engineering and Design, 333, p.87 - 98, 2018/07

 Times Cited Count:11 Percentile:34.62(Nuclear Science & Technology)

Journal Articles

A Large-scale numerical simulation of bubbly and liquid film flows in narrow fuel channels

Takase, Kazuyuki; Yoshida, Hiroyuki; Ose, Yasuo*; Akimoto, Hajime

Proceedings of 2005 ASME International Mechanical Engineering Congress and Exposition (CD-ROM), 8 Pages, 2005/11

no abstracts in English

Journal Articles

Numerical predictions on a large-scale bubbly flow configuration in a minichannel

Takase, Kazuyuki; Yoshida, Hiroyuki; Akimoto, Hajime; Ose, Yasuo*; Aoki, Takayuki*

Nihon Kikai Gakkai 2005-Nendo Nenji Taikai Koen Rombunshu, Vol.7, p.17 - 18, 2005/09

no abstracts in English

Journal Articles

Helium-air counter flow in rectangular channels

Fumizawa, Motoo; Tanaka, Gaku*; Zhao, H.*; Hishida, Makoto*; Shiina, Yasuaki

Nihon Genshiryoku Gakkai Wabun Rombunshi, 3(4), p.313 - 322, 2004/12

This paper deals with a computer simulation of a helium-air counter flow in a rectangular channel. The inclination angle is varied from 0$$^{circ}$$(horizontal) to 90$$^{circ}$$(vertical). Velocity profiles and concentration profiles are calculated with a computer program VSOP sub-module. Following main features of the counter flow are discussed. (1) Time required to establish a quasi-steady state counter flow. (2) The relationship between the inclination angle and the flow patterns of the counter flow (3) The developing process of velocity profiles and concentration profiles (4) The relationship between the inclination angle of the channel and the velocity profiles of upwards flow and the downwards flow (5) The relationship between the concentration profile and the inclination angle (6) The relationship between the net in-flow rate and the inclination angle We compared the computed velocity profile and the net in-flow rate with experimental data. A good agreement is obtained between the calculation and the experiment.

Journal Articles

Numerical analysis of a water-vapor two-phase film flow in a narrow coolant channel with a three-dimensional rectangular rib

Takase, Kazuyuki; Yoshida, Hiroyuki; Ose, Yasuo*; Tamai, Hidesada

JSME International Journal, Series B, 47(2), p.323 - 331, 2004/05

no abstracts in English

Journal Articles

Study on gas-liquid two-phase flow distribution in a tight-lattice rod bundle

Onuki, Akira; Shibata, Mitsuhiko; Tamai, Hidesada; Akimoto, Hajime; Yamauchi, Toyoaki*; Mizokami, Shinya*

Nihon Konsoryu Gakkai Nenkai Koenkai 2003 Koen Rombunshu, p.35 - 36, 2003/07

Analytical evaluation of maximum critical power by so-called subchannnel code is indispensable for design of reduced moderation water reactor. In this study, two-phase flow distribution in a tight-lattice rod bundle is investigated using 19-rod bundle experimental rig and subchannnel analysis code NASCA. The flow distribution was measured under so-called churn flow regime and the predictive capability of NASCA was assessed. NASCA can predict the flow distribution qualitatively depending on local pressure drop. Quantitative prediction is also reasonable for liquid phase but the gas phase distribution was underestimated. Void-drift model has a dominant contribution and we should improve the model for the tight-lattice rod bundle.

JAEA Reports

Measurement of coolant flow in fuel elements at the JRR-4 silicide fuel core

Yamamoto, Kazuyoshi; Watanabe, Shukichi; Nagatomi, Hideki; Kaminaga, Masanori; Funayama, Yoshiro

JAERI-Tech 2002-034, 40 Pages, 2002/03

JAERI-Tech-2002-034.pdf:1.97MB

JRR-4, a swimming-pool type research reactor with a thermal power of 3.5MW, attained criticality in July 1998, after replacing its 90% enrichment fuel with a 20% enrichment fuel under the Reduced Enrichment Program. As a part of the program, safety analysis on thermo-hydraulics of the reactor core was conducted on cases including single channel blockage accident. With the conclusion that a certain margin on thermo-hydraulics was necessary, investigation and experiments were carried out with an aim to increase the core flow rate. To increase the core flow, it was carried out to reduce the bypass flow in the core and to increase the primary coolant flow rate from 7m$$^{3}$$/min to 8m$$^{3}$$/min. After flow measurements using a mock-up fuel element, flow velocity of the fuel channel was determined as 1.45m/s as opposed to the designed value of 1.44m/s, and the ratio of core flow to total flow was 0.88, exceeding the value 0.86 used for the safety analysis.This report describes the JRR-4 core flow increase plan as well as the results of the channel flow rate measurement

Journal Articles

Critical heat flux at high velocity channel flow with high subcooling

Sudo, Yukio; Kaminaga, Masanori

Nucl. Eng. Des., 187, p.215 - 227, 1999/00

 Times Cited Count:7 Percentile:49.64(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Improvement of critical heat flux correlation for research reactors using plate-type fuel

Kaminaga, Masanori; Yamamoto, Kazuyoshi; Sudo, Yukio

Journal of Nuclear Science and Technology, 35(12), p.943 - 951, 1998/12

 Times Cited Count:24 Percentile:85.13(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Journal Articles

Applicability of ultrasonic velocity profile meter to horizontal open-channel flows and vortex shedding behind a cylinder

Nakamura, Hideo; ; *; Tsuji, Yoshiyuki*; Kukita, Yutaka*

Bulletin of the Research Laboratory for Nuclear Reactors, (SPECIAL ISSUE 2), p.35 - 46, 1997/00

no abstracts in English

Journal Articles

Improvement of CHF correlations for research reactors using plate-type fuels

Kaminaga, Masanori; Yamamoto, Kazuyoshi; Sudo, Yukio

Proceedings of 8th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics (NURETH-8), Vo.3, p.1815 - 1822, 1997/00

In research reactors, plate-type fuel elements are generally adopted so as to produce high power densities and are cooled by a downward flow. A core flow reversal from a steady-state forced downward flow to an upward flow due to natural convection should occur during operational transients such as "Loss of the primary coolant flow". Therefore, in the thermal hydraulic design of research reactors, critical heat flux (CHF) under a counter-current flow limitation (CCFL) or a flooding condition are important to determine safety margins of fuel against CHF during a core flow reversal. The authors have proposed a CHF correlation scheme for the thermal hydraulic design of research reactors, based on CHF experiments for both upward and downward flows including CCFL condition. When the CHF correlation scheme was proposed, a subcooling effect for CHF correlation under CCFL condition had not been considered because of a conservative evaluation and a lack of enough CHF data to determine the subcooling effect on CHF. A too conservative evaluation is not appropriate for the design of research reactors because of construction costs etc. Also, conservativeness of the design must be determined precisely. In this study, therefore, the subcooling effect on CHF under the CCFL conditions in vertical rectangular channels heated from both sides were investigated quantitatively based on CHF experimental results obtained under uniform and nonuniform heat flux condition. As a result, it was made clear that CHF in this region increase linearly with an increase of the channel inlet subcooling and a new CHF correlation including the effect of channel inlet subcooling was proposed.

Journal Articles

JAEA Reports

Steady-state thermal hydraulic analysis and flow channel blockage accident analysis of JRR-4 silicide LEU core

Kaminaga, Masanori; Yamamoto, Kazuyoshi; Watanabe, Shukichi

JAERI-Tech 96-039, 72 Pages, 1996/09

JAERI-Tech-96-039.pdf:2.43MB

no abstracts in English

JAEA Reports

Benchmark calculation of subchannel analysis codes

JAERI-Data/Code 96-004, 109 Pages, 1996/02

JAERI-Data-Code-96-004.pdf:2.3MB

no abstracts in English

Journal Articles

Flow reversal in a horizontal channel with mixed convection

*; Kunugi, Tomoaki; *

Album of Visualization,No. 13, 0, p.19 - 20, 1996/00

no abstracts in English

Journal Articles

Three-dimensional numerical analysis of mixed convective heat transfer in a horizontal square channel with heated and cooled side walls

*; Kunugi, Tomoaki; *

Nihon Kikai Gakkai Rombunshu, B, 61(586), p.2228 - 2234, 1995/06

no abstracts in English

45 (Records 1-20 displayed on this page)