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Journal Articles

Development of prediction technology of two-phase flow dynamics under earthquake acceleration, 16; Experimental and numerical study of pressure fluctuation effects on bubble motion

Kato, Yuki; Yoshida, Hiroyuki; Yokoyama, Ryotaro*; Kanagawa, Tetsuya*; Kaneko, Akiko*; Monji, Hideaki*; Abe, Yutaka*

Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 8 Pages, 2015/05

Journal Articles

Development of prediction technology of two-phase flow dynamics under earthquake acceleration

Yoshida, Hiroyuki; Nagatake, Taku; Takase, Kazuyuki; Kaneko, Akiko*; Monji, Hideaki*; Abe, Yutaka*

Mechanical Engineering Journal (Internet), 1(4), p.TEP0025_1 - TEP0025_11, 2014/08

Journal Articles

Development of prediction technology of two-phase flow dynamics under earthquake acceleration, 14; Numerical simulation of two-phase flow in subchannels under accelerating condition

Yoshida, Hiroyuki; Nagatake, Taku; Takase, Kazuyuki; Kaneko, Akiko*; Monji, Hideaki*; Abe, Yutaka*

Proceedings of 22nd International Conference on Nuclear Engineering (ICONE-22) (DVD-ROM), 10 Pages, 2014/07

Journal Articles

Development of prediction technology of two-phase flow dynamics under earthquake acceleration, 10; Numerical prediction of velocity profile around bubble under accelerating condition

Yoshida, Hiroyuki; Nagatake, Taku; Takase, Kazuyuki; Kaneko, Akiko*; Monji, Hideaki*; Abe, Yutaka*

Proceedings of 21st International Conference on Nuclear Engineering (ICONE-21) (DVD-ROM), 10 Pages, 2013/07

Journal Articles

Numerical simulation of rising bubble behavior under accelerating conditions

Yoshida, Hiroyuki; Nagatake, Taku; Takase, Kazuyuki; Kaneko, Akiko*; Monji, Hideaki*; Abe, Yutaka*

Dai-62-Kai Riron Oyo Rikigaku Koenkai Koen Rombunshu (USB Flash Drive), 2 Pages, 2013/03

no abstracts in English

Journal Articles

Journal Articles

Numerical prediction of two-phase flow behavior under seismic condition by use of interface tracking method

Yoshida, Hiroyuki; Nagatake, Taku; Takase, Kazuyuki; Kaneko, Akiko*; Monji, Hideaki*; Abe, Yutaka*

Proceedings of 8th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-8) (USB Flash Drive), 9 Pages, 2012/12

Journal Articles

Numerical prediction of two-phase flow behavior under seismic condition by use of interface tracking method

Yoshida, Hiroyuki; Nagatake, Taku; Takase, Kazuyuki; Kaneko, Akiko*; Monji, Hideaki*; Abe, Yutaka*

Nippon Kikai Gakkai Dai-25-Kai Keisan Rikigaku Koenkai Rombunshu (CD-ROM), p.693 - 695, 2012/10

no abstracts in English

Journal Articles

Investigation on fluid-structure thermal interaction related to Eddy structure on branch jet in T-junction

Tanaka, Masaaki; Takita, Hiroki*; Monji, Hideaki*; Ohshima, Hiroyuki

Nippon Kikai Gakkai Rombunshu, B, 78(792), p.1462 - 1465, 2012/08

Water experiment and numerical simulation under thermal interaction conditions between fluid and structure were conducted for a T-junction piping system. In the experiment, temperatures at 2 mm from the wall in fluid, on the wall and at 3 mm inside from the wall in structure along a vertical trace line were measured simultaneously. Numerical results indicated that the fluid temperature distribution near the wall was much affected by the thermal interaction with the structure and that fluid-structure thermal interaction was necessarily considered for thermal fatigue estimation in the thermal striping phenomena.

Journal Articles

Development of prediction technology of two-phase flow dynamics under earthquake acceleration, 6; Numerical simulation of bubble deformation near wall under accelerating condition

Yoshida, Hiroyuki; Nagatake, Taku; Takase, Kazuyuki; Kaneko, Akiko*; Monji, Hideaki*; Abe, Yutaka*

Proceedings of 20th International Conference on Nuclear Engineering and the ASME 2012 Power Conference (ICONE-20 & POWER 2012) (DVD-ROM), 8 Pages, 2012/07

Journal Articles

Numerical simulation of two-phase flow behavior under earthquake acceleration

Yoshida, Hiroyuki; Takase, Kazuyuki; Kaneko, Akiko*; Monji, Hideaki*; Abe, Yutaka*

Proceedings of IEEE PES Asia-Pacific Power and Energy Engineering Conference 2012 (APPEEC 2012) (CD-ROM), 4 Pages, 2012/03

Journal Articles

Investigation on fluid-structure thermal interaction related to eddy structure on branch jet in T-junction

Tanaka, Masaaki; Takita, Hiroki*; Monji, Hideaki*; Ohshima, Hiroyuki

Dai-16-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu, p.223 - 224, 2011/06

Water experiment and numerical simulation under thermal interaction conditions between fluid and structure were conducted for a T-junction piping system (T-pipe) consisting of a rectangular duct for main stream and a circular pipe for branch stream. Numerical results were compared with the experimental results and indicated that the fluid-structure thermal interaction was necessarily considered for thermal fatigue estimation in the thermal striping phenomena because fluid temperature distribution near the wall was much affected by the thermal interaction.

Journal Articles

Numerical investigation on thermal mixing related to eddy structure in T-junction

Tanaka, Masaaki; Kurokawa, Koji*; Takita, Hiroki*; Monji, Hideaki*; Ohshima, Hiroyuki

Nippon Kikai Gakkai Rombunshu, B, 77(776), p.969 - 973, 2011/04

Numerical simulations for a T-pipe consisting of a rectangular duct for main stream and a circular pipe for branch stream were performed to investigate relation between large-scale eddy structure formation in the mixing area and temperature fluctuation generation on the wall. Moreover, the numerical simulation to investigate thermal interaction between fluid and structure were conducted. Experimental results of temperatures at 2 mm from the wall in fluid, on the wall and at 3 mm inside from the wall in structure were compared with those of the numerical results. The numerical results indicate that the fluid-structure thermal interaction is necessarily considered for thermal fatigue estimation in the thermal striping phenomena.

Journal Articles

Thermal mixing in T-junction piping system related to high-cycle thermal fatigue in structure

Tanaka, Masaaki; Ohshima, Hiroyuki; Monji, Hideaki*

Journal of Nuclear Science and Technology, 47(9), p.790 - 801, 2010/09

Numerical simulation of thermal striping phenomena in a T-junction piping system (JAEA WATLON experiment) was conducted by using the numerical simulation code "MUGTHES", which has been developed at JAEA. MUGTHES employs the large eddy simulation (LES) approach and standard Smagorinsky model as a turbulence eddy viscosity model with the model coefficient of 0.14 (=$$Cs$$). Numerical results were validated by comparisons with the experimental results of velocity and temperature. Applicability of MUGTHES to the thermal striping phenomena in the T-pipe was confirmed and the characteristic large-scale hairpin vortex structure which dominates thermal mixing and may cause high-cycle thermal fatigue was revealed.

Journal Articles

Improvement of gas entrainment prediction method; Introduction of surface tension effect

Ito, Kei; Sakai, Takaaki; Eguchi, Yuzuru*; Monji, Hideaki*; Ohshima, Hiroyuki; Uchibori, Akihiro; Xu, Y.*

Journal of Nuclear Science and Technology, 47(9), p.771 - 778, 2010/09

A gas entrainment (GE) prediction method has been developed to establish design criteria for the large-scale sodium-cooled fast reactor (JSFR) systems. In this paper, the evaluation accuracy of gas core lengths is improved by introducing the surface tension effects into the prototype GE prediction method. For the improvement, the mechanical balance between gravitational, centrifugal, and surface tension forces is considered. The improved GE prediction method is validated by analyzing the gas core lengths observed in simple experiments. Results show that the analytical gas core lengths calculated by the improved GE prediction method become shorter in comparison to the prototype GE prediction method, and are in good agreement with the experimental data. In addition, the experimental data under different temperature and surfactant concentration conditions are reproduced by the improved GE prediction method.

Journal Articles

Numerical investigation on thermal mixing related to eddy structure in T-junction

Tanaka, Masaaki; Kurokawa, Koji*; Takita, Hiroki*; Monji, Hideaki*; Ohshima, Hiroyuki

Dai-15-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu, p.221 - 224, 2010/06

Numerical simulations for a T-pipe consisting of a rectangular duct for main stream and a circular pipe for branch stream were performed to investigate relation between large-scale eddy structure formation in the mixing area and temperature fluctuation generation on the wall. Water experiment and numerical simulation in the T-pipe to investigate fluid-structure thermal interaction were conducted. The numerical results indicate that the fluid-structure thermal interaction is necessarily considered for thermal fatigue estimation in the thermal striping phenomena.

Journal Articles

Experimental study on thermal mixing related to eddy structure in T-junction

Tanaka, Masaaki; Kurokawa, Koji*; Takita, Hiroki*; Monji, Hideaki*

Nippon Kikai Gakkai Rombunshu, B, 76(763), p.463 - 465, 2010/03

In this study, a simplified T-junction piping system consisting of a rectangular duct for main stream and a circular pipe for branch stream was used as the test section in the water experiment. Time series of instantaneous two-dimensional velocity fields were obtained by PIV (Particle Image Velocimetry) in the mixing area. And fluid temperature fluctuations at several positions at 2 mm inside from the wall were also measured by thermo-couples. Focusing on the frequency characteristics, formation of eddy structure in the mixing area and mutual relation between the temperature fluctuation generation and the flow structure were discussed.

Journal Articles

Effect of experimental conditions on gas core length and downward velocity of free surface vortex in cylindrical vessel

Monji, Hideaki*; Shinozaki, Tatsuya*; Kamide, Hideki; Sakai, Takaaki

Journal of Engineering for Gas Turbines and Power, 132(1), p.012901_1 - 012901_8, 2010/01

 Times Cited Count:7 Percentile:50.1(Engineering, Mechanical)

This paper deals with characteristics of surface vortex in a cylindrical vessel. One of the characteristics is a gas core length which is important to estimate the onset condition of the gas entrainment but influenced easily by the experimental condition. In the experiment using water, the effects of the water temperature, water level and the surface tension on the gas core length were investigated. The onset condition of the gas entrainment is sometimes estimated by using the Burgers vortex model but the real flow in the vessel is different from the model. The velocity fields were measured by PIV and the velocity gradient of the downward flow was discussed. The proper flow conditions for the Burgers vortex model are a high water level and a high flow rate.

Journal Articles

Numerical investigation of flow structure in pipe elbow with large eddy simulation approach

Tanaka, Masaaki; Ohshima, Hiroyuki; Monji, Hideaki*

Proceedings of 2009 ASME Pressure Vessels and Piping Division Conference (PVP 2009) (CD-ROM), 10 Pages, 2009/07

We have been developing a numerical simulation code "MUGTHES". MUGTHES employs large eddy simulation approach to calculate unsteady thermal-hydraulic phenomena and the boundary fitted coordinate system to model complex geometry in systems precisely. In this study, numerical simulations were conducted for pipe elbow flows in various curvature radius ratio conditions at several Reynolds number conditions. Through these simulations, applicability of MUGTHES to the elbow pipe flow was confirmed and the characteristics of three-dimensional flow structure that might influence on the structural integrity of the elbow pipe was discussed.

Journal Articles

Experimental study on thermal mixing related to eddy structure in T-junction

Tanaka, Masaaki; Kurokawa, Koji*; Takita, Hiroki*; Monji, Hideaki*

Dai-14-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu, p.449 - 450, 2009/06

In this study, a simplified T-junction piping system consisting of a rectangular duct for main stream and a circular pipe for branch stream was used as the test section. Time series of instantaneous pictures in two-dimensional velocity vector field were obtained by PIV technique. And fluid temperature fluctuations at 2 mm inside from the wall were also measured by thermo-couples. Focusing on the frequency characteristics, formation of eddy structure in the mixing area and mutual relation between the temperature fluctuation generation and the flow structure were discussed.

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