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Yoshida, Hiroyuki; Suzuki, Takayuki*; Takase, Kazuyuki
Nihon Konsoryu Gakkai Nenkai Koenkai 2010 Koen Rombunshu, p.344 - 345, 2010/07
no abstracts in English
Nakatsuka, Toru; Misawa, Takeharu; Yoshida, Hiroyuki; Takase, Kazuyuki
Nihon Konsoryu Gakkai Nenkai Koenkai 2010 Koen Rombunshu, p.348 - 349, 2010/07
In the thermal hydraulic design of supercritical water-cooled reactor, it is required to establish a thermal hydraulic design method which can precisely predict heat transfer deterioration of supercritical water as the core coolant. Assessments of applicability of turbulence models used in design methods have not been sufficiently performed, since the mechanism of heat transfer deterioration has not been clearly figured out yet. Japan Atomic Energy Agency has started developing prediction method of heat transfer deterioration with large eddy simulation to improve the thermal hydraulic design accuracy. In the present study, simulation results of heat transfer test with Freon are reported.
Misawa, Takeharu; Yoshida, Hiroyuki; Takase, Kazuyuki
Nihon Konsoryu Gakkai Nenkai Koenkai 2010 Koen Rombunshu, p.92 - 93, 2010/07
no abstracts in English
Ito, Kei; Kunugi, Tomoaki*; Ohshima, Hiroyuki
no journal, ,
For the purpose of direct simulations of gas entrainment (GE) phenomenon in fast reactors, the authors are developing a high-precision simulation algorithms for gas-liquid two-phase flows on unstructured meshes. In this study, the calculation method for interfacial gradient is improved by developing a height function algorithm which determine the interfacial gradient based on least-square concept on unstructured meshes. As a result of basic verifications, the height function algorithm succeeds in reproducing rectilinear interfaces on an unstructured triangular mesh. In addition, interfacial curvature is calculated accurately on high resolution meshes based on the height function algorithm. Therefore, it is confirmed that the developed height function algorithm can enhance the simulation accuracy of gas-liquid two-phase flows.
Koizumi, Yasuo*; Ito, Kei; Ohshima, Hiroyuki; Otake, Hiroyasu*
no journal, ,
Gas entrainment from the bottom of a container was examined in the case that there was a free surface with swirl flow and liquid flew out from an outlet at the bottom. Before the bottom of the vortex reached the bottom of the container, bubble-state gas entrainment from the tip of the vortex occurred and the bubbles flew out from the bottom outlet of the container. As the liquid velocity was increased, the bottom of the vortex invaded into the outlet piping and eventually air and liquid phase separation occurred in the piping. The flow state changed to a churn flow, and then to an annular flow and the entrained air flow rate increased considerably as the liquid flow rate was increased.