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Ito, Kei; Ezure, Toshiki; Ohshima, Hiroyuki; Kawamura, Takumi*; Nakamine, Yoshiaki*
Proceedings of 9th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-9) (CD-ROM), 6 Pages, 2014/11
The authors have been studied the vortex cavitation in sodium-cooled fast reactors. In this paper, the authors present a modified evaluation method for vortex cavitation, in which a surface tension is modeled mechanistically. Namely, the cavity radius is calculated in consideration of radial pressure distribution, saturated vapor pressure and the pressure jump condition at an interface. As the basic validation of the developed surface tension model, numerical analyses of a simple experiment under various velocity conditions are performed. The evaluation results give qualitatively appropriate tendency, that is, the cavity radius becomes larger with the higher liquid velocity and/or lower reference pressure which cause the larger pressure drop at the vortex. In addition, the authors evaluate the influence of the kinematic viscosity which plays an important role in the vortex cavitation occurrences in the experiments.
Ito, Kei; Ezure, Toshiki; Ohno, Shuji; Nakamine, Yoshiaki*; Kawamura, Takumi*
no journal, ,
In Japan Atomic Energy Agency, an evaluation method for the submerged-vortex cavitation at a pipe intake has been examined as a part of the establishment of the safety design criteria for a sodium-cooled fast reactor. The submerged-vortex cavitation is nonlinear and highly complicated phenomenon, and therefore it is difficult to predict the occurrence condition based on the macroscopic quantities, e.g. the flow rate. In this study, the authors proposes a new evaluation method based on a three-dimensional CFD.
Ito, Kei; Koizumi, Yasuo*; Ezure, Toshiki; Ohno, Shuji; Kamide, Hideki; Kawamura, Takumi*
no journal, ,
We have been developing a quantitative evaluation method for the gas entrainment phenomenon in sodium-cooled fast reactors. In this report, numerical simulations are performed to evaluate the influence of fluid property on the gas entrainment flow rate.
Ito, Kei; Ezure, Toshiki; Ohshima, Hiroyuki; Kawamura, Takumi*; Nakamine, Yoshiaki*
no journal, ,
The prevention of vortex cavitation is one of key factors in the safety design criteria for sodium-cooled fast reactors. Therefore, the authors have developed a CFD-based evaluation method to determine the occurrence of the vortex cavitation. In this paper, the accuracy of the evaluation method is enhanced by developing a surface tension model by which the cavity radius is calculated in consideration of radial pressure distribution, saturated vapor pressure and the pressure jump condition at an interface. As a basic validation of the developed surface tension model, numerical analyses of a simple experiment under various velocity and pressure conditions are performed. The evaluation results give qualitatively appropriate cavity radius which becomes larger with the higher liquid velocity and/or lower reference pressure. Therefore, the developed surface tension model is considered to be physically-appropriate.
Terada, Atsuhiko; Ezure, Takumi*; Hino, Ryutaro; Sugiyama, Hitoshi*; Takase, Kazuyuki*
no journal, ,
A new type passive autocatalytic recombiner has been developed, as one of hydrogen safety managements for waste storage. In this report, thermal hydraulic analysis show PAR concept proposed is feasible for hydrogen mitigation in small scale test.