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Kureta, Masatoshi
Ryutai Keisokuho; Kaitei-Han, p.367 - 371, 2022/04
The Japan Society of Mechanical Engineers publishes a revised version of the technical document summarizing fluid measurement techniques. This article is part of the application section, and the main content is an introduction of application examples using advanced thermal-fluid measurement technology that is progressing remarkably. In the chapter "Void Fraction Distribution Measurement", the technology for visualizing and measuring the void fraction distribution with neutron beams for the two-phase flow of gas-liquid flowing inside the instrument is summarized. In the first half, the definition of void fraction, measurement by neutron transmission method, and basic principles of CT imaging technology were explained. In the second half, visualization and measurement results were shown in the order of two-dimensional and two-dimensional time changes of various multiphase flows, and three-dimensional and three-dimensional time changes.
Ito, Daisuke*; Ito, Kei*; Saito, Yasushi*; Aoyagi, Mitsuhiro; Matsuba, Kenichi; Kamiyama, Kenji
Nuclear Engineering and Design, 334, p.90 - 95, 2018/08
Times Cited Count：9 Percentile：62.99(Nuclear Science & Technology)Two-phase flow through porous media must be well understood to develop a severe accident analysis code not only for light water reactor but also sodium-cooled fast reactor. When a core disruptive accident occurs in sodium-cooled fast reactor, the fuel inside the core become melted and interacts with the coolant. As a result, gas-liquid two-phase flow will be formed in the debris bed, which may have porous nature depending on the cooling process. In such condition, the local porosity and its distribution are very important to characterize two-phase flow field in the porous media. In this study, X-ray radiography was applied to measure the local porosity in the packed bed of spheres. The radial profiles were estimated from the chordal profiles measured by the X-ray method and compared with the previous porosity model. In addition, the void fraction radial profiles were also obtained in air-water two-phase flow.
4 rod bundleLiu, W.; Jiao, L.; Nagatake, Taku; Shibata, Mitsuhiko; Komatsu, Masao*; Takase, Kazuyuki*; Yoshida, Hiroyuki
Proceedings of 11th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, Operation and Safety (NUTHOS-11) (USB Flash Drive), 10 Pages, 2016/10
To contribute the clarification of the Fukushima Daiichi Accident, Japan Atomic Energy Agency (JAEA) has been performed experiments to obtain void fraction distribution data, including detailed bubble information such as bubble velocity and size, in steam-water two-phase flow in rod bundle geometry under high pressure and high temperature condition, focusing on low flow rate at the core natural circulation flow condition after the reactor scram. In this research, experimental apparatus for measuring void fraction distribution in the 44 rod bundle was constructed. To measure the void fraction distribution under high pressure and high temperature condition (up to 2.8 MPa, 232 
C), two wire mesh sensors (WMSs) were installed. To confirm the applicability of the installed WMSs and the measuring system for two-phase flow in rod bundle, experiments in air-water two-phase flow under atmospheric pressure and room temperature were performed. As a result, it was confirmed that the installed WMSs can be applicable to the two-phase flow in rod bundle. Measured results, such as instantaneous and time-averaged void fraction distribution in the rod bundle, average void fraction across the cross section of the flow channel, bubble length and velocity, were also reported.
Sakka, Taku*; Jiao, L.; Uesawa, Shinichiro; Yoshida, Hiroyuki; Takase, Kazuyuki
Nihon Kikai Gakkai 2015-Nendo Nenji Taikai Koen Rombunshu (DVD-ROM), 5 Pages, 2015/09
no abstracts in English
Ose, Yasuo*; Takase, Kazuyuki; Yoshida, Hiroyuki; Kano, Takuma; Akimoto, Hajime
Dai-18-Kai Suchi Ryutai Rikigaku Shimpojiumu Koen Yoshishu (CD-ROM), 6 Pages, 2004/12
no abstracts in English
Kureta, Masatoshi
Kashika Joho Gakkai-Shi, 24(Suppl.1), p.265 - 268, 2004/07
Visualization of 3D and instantaneous void fraction distribution of boiling flow in a tight-lattice 14-rod bundle is conducted by using neutron tomography and high-frame- rate neutron radiography void fraction measurement techniques. The purpose of the experiment is to understand vapor bubbles/water behavior ranging from the onset of boiling to the high void fraction region based on ("3D" + "2D+Time") void fraction data, and to obtain the fine-mesh database for verification of advanced analysis codes. Following phenomena are made clear from the present experiment: Vapor accumulates in the channel center; High void fraction spots appear between adjacent heater rods, that is, in narrow space at the inlet; Void fraction in the triangular space among three rods becomes high by void drift phenomenon, and "vapor chimney" is formed; Flow is intermittent, and vapor bubble clusters are formed periodically; Onset points of net vapor generation are scattered not only in the center but in the peripheral.
Takase, Kazuyuki; Yoshida, Hiroyuki; Ose, Yasuo*
Dai-23-Kai Nihon Shimyureshon Gakkai Taikai Happyo Rombunshu, p.121 - 124, 2004/06
no abstracts in English
Kureta, Masatoshi; Tamai, Hidesada
Proceedings of 5th International Conference on Multiphase Flow (ICMF 2004) (CD-ROM), 10 Pages, 2004/06
3D void fraction distribution of boiling flow in a tight-lattice 7-rod bundle was measured by neutron radiography 3D computed tomography (neutron tomography) to investigate the flow characteristics in tight-lattice rod bundles and to verify the numerical analysis codes. The test section simulates the fuel rod bundle of the RMWR and consists of 7 heater rods with gap of 1.0mm and with diameter of 12.0mm. In this paper, the neutron tomography system, experiments and comparison of the measured data with a subchannel analysis code, COBRA-TF, are reported. It was found from this experiment that water layer which surrounds the heater rod becomes thick between rods, narrow region, and steam accumulates at the center region among three rods. COBRA-TF code overestimates the void fraction in a tight-lattice bundle compared with the present data.
Ose, Yasuo*; Takase, Kazuyuki; Yoshida, Hiroyuki; Kano, Takuma; Kureta, Masatoshi; Akimoto, Hajime
Dai-41-Kai Nihon Dennetsu Shimpojiumu Koen Rombunshu, 2 Pages, 2004/05
no abstracts in English
Takase, Kazuyuki; Yoshida, Hiroyuki; Ose, Yasuo*; Tamai, Hidesada; Akimoto, Hajime
Transactions of the American Nuclear Society, 89, p.88 - 89, 2003/11
no abstracts in English
Kureta, Masatoshi
Funryu Kogaku, 20(2), p.24 - 31, 2003/07
no abstracts in English
Shibamoto, Yasuteru; Sagawa, Jun*; Iguchi, Tadashi; Nakamura, Hideo
JAERI-Tech 2003-056, 29 Pages, 2003/06
JAERI-Tech-2003-056.pdf:3.24MB
no abstracts in English
Kureta, Masatoshi
Kashika Joho Gakkai-Shi, 23(89), p.21 - 26, 2003/04
no abstracts in English
Kureta, Masatoshi; Hibiki, Takashi*; Mishima, Kaichiro*; Akimoto, Hajime
International Journal of Heat and Mass Transfer, 46(7), p.1171 - 1181, 2003/03
Times Cited Count：13 Percentile：49.26(Thermodynamics)no abstracts in English
Takase, Kazuyuki; Ose, Yasuo*; Akimoto, Hajime
Fusion Engineering and Design, 63-64, p.429 - 436, 2002/12
Times Cited Count：5 Percentile：34.58(Nuclear Science & Technology)no abstracts in English
Matsubayashi, Masahito
Hihakai Kensa No Saizensen (CD-ROM), 7 Pages, 2002/00
no abstracts in English
Kureta, Masatoshi; Akimoto, Hajime
Proceedings of 10th International Symposium on Flow Visualization (ISFV-10) (CD-ROM), 8 Pages, 2002/00
no abstracts in English
Kureta, Masatoshi; Akimoto, Hajime; Hibiki, Takashi*; Mishima, Kaichiro*
Nuclear Technology, 136(2), p.241 - 254, 2001/11
Times Cited Count：11 Percentile：61.99(Nuclear Science & Technology)no abstracts in English
Kureta, Masatoshi
KURRI-KR-70, p.136 - 147, 2001/10
no abstracts in English
Kureta, Masatoshi; Hibiki, Takashi*; Mishima, Kaichiro*; Akimoto, Hajime
Nihon Kikai Gakkai Rombunshu, B, 67(661), p.2295 - 2303, 2001/09
no abstracts in English
