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Iwasawa, Yuzuru*; Abe, Yutaka*; Kaneko, Akiko*; Kanagawa, Tetsuya*; Saito, Shimpei*; Matsuo, Eiji*; Ebihara, Kenichi; Sakaba, Hiroshi*; Koyama, Kazuya*; Nariai, Hideki*
Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 7 Pages, 2015/05
For the safety design in which heat is properly removed from the molten fuel after the core disruptive accident in a sodium-cooled fast reactor, the estimation of the breakup behavior of molten fuel discharged into the coolant like a jet is desired. In order to investigate the influence of viscocity on the jet behavior, we simulated a jet discharged into a coolant using the three-dimensional lattice Boltzmann model for two-phase fluid, and examined the influence of Ohnesorge number and Reynolds number on the jet behavior. As a result, we made clear that it is necessary to consider viscosity of the coolant as well as that of the jet for the estimation of jet behavior.
Iwasawa, Yuzuru*; Abe, Yutaka*; Kaneko, Akiko*; Kuroda, Taihei*; Matsuo, Eiji*; Ebihara, Kenichi; Sakaba, Hiroshi*; Koyama, Kazuya*; Ito, Kazuhiro*; Nariai, Hideki*
Proceedings of 15th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-15) (USB Flash Drive), 12 Pages, 2013/05
In the safety design of a Fast Breeder Reactor(FBR), when it is supposed that a Core Disruptive Accident(CDA) occurs, it is strongly required that molten core materials are completely solidified and are cooled down by sodium coolant in a reactor vessel. In this study, we injected molten alloy and transparent fluid, which are a simulant of the molten core material, into water, which is a simulant of the coolant. In this study, we injected molten alloy and transparent fluid, which simulate the molten core material, into water, which simulates the coolant. In the experiment, we observed the jet breakup behavior of them using a high speed video camera, and compared the observe images with the previous theories. In addition, we simulated numerically the qualitative behavior of the liquid jet using a two-phase fluid model of the lattice Boltzmann method.
Liu, W.; Nariai, Hideki*
Journal of Heat Transfer, 127(2), p.149 - 158, 2005/02
Times Cited Count:11 Percentile:46.13(Thermodynamics)Homogeneous nucleation, although being discounted as a mechanism for vapor formation for water in most conditions, is found being possible to occur under some extreme conditions in subcooled flow boiling. In this paper, firstly, the existence of the homogeneous nucleation governed condition is indicated. Followed, a criterion is developed to judge a given working condition is the conventional one or the homogeneous nucleation governed one. With the criterion, subcooled flow boiling data are categorized and typical homogeneous nucleation governed datasets are listed. CHF triggering mechanism for the homogeneous nucleation governed condition is proposed and verified. Parametric trends of the CHF, in terms of mass flux, pressure, inlet subcooling, channel diameter and the ratio of heated length to diameter are also studied.
Nariai, Hideki*
JAERI-Tech 2002-009, 60 Pages, 2002/03
no abstracts in English
Kinoshita, Hidetaka; Nariai, Hideki*; Inasaka, Fujio*
JSME International Journal, Series B, 44(1), p.81 - 89, 2001/01
no abstracts in English
Kusunoki, Tsuyoshi; Ito, Toshio*; Nariai, Hideki*
Nihon Kikai Gakkai 2000-Nendo Nenji Taikai Koen Rombunshu, p.645 - 646, 2000/08
no abstracts in English
Nariai, Hideki*; Sugiyama, Kenichiro*; Kataoka, Isao*; Mishima, Kaichiro*; *; Monde, Masanori*; Sugimoto, Jun; ; Hidaka, Akihide; *; et al.
Nihon Genshiryoku Gakkai-Shi, 39(9), p.739 - 752, 1997/00
Times Cited Count:1 Percentile:10.53(Nuclear Science & Technology)no abstracts in English
Iwasawa, Yuzuru*; Abe, Yutaka*; Kaneko, Akiko*; Saito, Shimpei*; Matsuo, Eiji*; Ebihara, Kenichi; Sakaba, Hiroshi*; Koyama, Kazuya*; Nariai, Hideki*
no journal, ,
Since there is a possibility that molten core is spouted out into coolant in the case of the core disruptive accident of a fast breeder reactor, it is important to predict the jet breakup length, which is the distance that the jet reaches, for proper cooling. The previous report discusses the adaptability of the simulation by the lattice Boltzmann model to the experiment of liquid jet by comparing to the experiment with air entrainment which is not considered in the model. In this presentation, we discussed the mechanism of jet breakup by comparing the simulation to the experiment without air entrainment. As a result, the model reproduced the jet behavior without air entrainment well, and the dimensionless number regarding the jet breakup length was almost same with that of the experiment. In addition, according to the flow velocity distribution obtained from the simulation, it was confirmed that vortexes at the leading-edge of the jet promote the jet breakup.
Iwasawa, Yuzuru*; Abe, Yutaka*; Kaneko, Akiko*; Kanagawa, Tetsuya*; Saito, Shimpei*; Matsuo, Eiji*; Ebihara, Kenichi; Sakaba, Hiroshi*; Koyama, Kazuya*; Nariai, Hideki*
no journal, ,
no abstracts in English