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Murai, Yuichi*; Oiwa, Hiroshi; Sasaki, Toshio*; Kondo, Masahiko; Yoshikawa, Shinji; Yamamoto, Fujio*
Measurement Science and Technology, 16(7), p.1459 - 1468, 2005/07
Times Cited Count:31 Percentile:81.38(Engineering, Multidisciplinary)Air-water two-phase flow in a helically coiled tube is investigated using backlight imaging tomography to elucidate the effect of centrifugal acceleration on phase distribution and interfacial structure. Superficial velocities up to 6m/s in 20mm-diameter tube are tested. We focused on a slug flow regime in which centrifugal acceleration dominates the flow. The interfacial structure is visualized in six directions using a set of originally designed mirror-mounted water jackets. A temporal expansion image is made from line-sampled images, and is used to reconstruct phase distribution through a linear backward projection algorithm. The present topography measurement showed various new features of gas-liquid two-phase flow in a helically coiled tube, such as a wall-covering effect in the case of high superficial velocity.
Oiwa, Hiroshi; Murai, Yuichi*; Sasaki, Toshio*; Yoshikawa, Shinji; Yamamoto, Fujio*
Proceedings of 4th World Congress on Industrial Process Tomography, Vol.1, p.428 - 433, 2005/00
We carried out reflection seismic and multi-offset VSP surveys at JNC Shobasama-site to develop the investigation technique in the granite area, and evaluated the applicability of these geophysical methods. As the result of this study, we consider that a) It is possible to infer the existence of the lower angle fracture zone in the granite by eflection seismic survey and b) Multi-offset VSP supplements the result of reflection seismic survey and it is possible to infer the distribution of the fracture zone in deeper area in the granite.
Murai, Yuichi*; Yamamoto, Fujio*; Ishikawa, Masaaki*; Sakai, Kosuke*; Oiwa, Hiroshi*; Toda, Shinichi; Yoshikawa, Shinji; Tamayama, Kiyoshi
JNC TY4400 2003-006, 75 Pages, 2003/06
None
Oiwa, Hiroshi
no journal, ,
no abstracts in English
Oiwa, Hiroshi; Murai, Yuichi*; Yoshikawa, Shinji
no journal, ,
Helically coiled type steam generator is used in Fast Breeder Reactor "Monju". The characteristics of this steam generator is affected by the centrifugal acceleration due to curvature of the heat transfer tube. The centrifugal acceleration forces the liquid phase to the wall of the tube. This phenomenon suppresses the rapid boiling that may induce the hydrodynamic oscillation. In this study, the effect of centrifugal acceleration and inlet conditions of the fluid is investigated by experiment using backlight imaging tomography and numerical simulation using CIP-level set method. We focused on a slug flow regime in which centrifugal acceleration dominates the flow. The present study showed two types of the centrifugal acceleration effects. One is the effect that holds the liquid phase near the tube wall, and another is the liquid-covering effect on the wall by secondary flow.
Oiwa, Hiroshi
no journal, ,
no abstracts in English
Oiwa, Hiroshi; Yoshikawa, Shinji
no journal, ,
Helically coiled heat transfer tubes are used in the steam generator of Fast Breeder Reactor "Monju". The characteristics of this steam generator is affected by the centrifugal acceleration due to curvature of the heat transfer tube. The centrifugal acceleration forces the liquid phase to the wall of the tube. This phenomenon suppresses the rapid boiling that may induce the hydrodynamic oscillation. In this study, the effect of centrifugal acceleration and inlet conditions of the fluid is investigated by numerical simulation using CIP-level set method. We focused on the slug flow regime in which centrifugal acceleration dominates the flow. The present study showed two types of the centrifugal acceleration effects. One is the effect that holds the liquid phase near the tube wall, and another is the liquid-covering effect on the wall by secondary flow.