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Iwamoto, Yukiharu*; Kusuzaki, Ryo*; Sogo, Motosuke*; Yasuda, Kazunori*; Yamano, Hidemasa; Tanaka, Masaaki
Proceedings of ASME-JSME-KSME Joint Fluids Engineering Conference 2015 (AJK 2015-FED) (USB Flash Drive), p.1767 - 1773, 2015/07
Wall pressure measurements and flow visualization were conducted for a 90 degree elbow of which the axis curvature radius became the same as its inner diameter (125 mm). A deflected inflow, having an almost constant velocity slope, was introduced. Ensemble averaged pressure distributions showed no normalized pressure difference in cases of Reynolds numbers of 320,000 and 500,000. Comparisons with uniform inlet flow case proved; low-pressure region at the intrados of the elbow was weakened whereas a high pressure region outside strengthened in the deflected inflow case. Pressure distribution downstream of the elbow increased at the inside until two diameters downstream from the elbow exit. Flow visualization showed the pressure increase from collision of a strengthened secondary flow of extrados convection. The unsteady pressure distribution showed a circumferential extent of a strongly fluctuating region in and downstream the elbow decreased, comparing with the uniform inlet flow case.
Iwamoto, Yukiharu*; Kondo, Manabu*; Yasuda, Kazunori*; Sogo, Motosuke*; Tanaka, Masaaki; Yamano, Hidemasa
Proceedings of 19th International Conference on Nuclear Engineering (ICONE-19) (CD-ROM), 10 Pages, 2011/10
Iwamoto, Yukiharu*; Sogo, Motosuke*; Aizawa, Kosuke; Nakanishi, Shigeyuki*; Yamano, Hidemasa
JAEA-Research 2010-009, 58 Pages, 2010/06
Experimental studies of the 1/10-scale model of a hot leg piping and their numerical analyses were carried out in order to guarantee the designing of the sodium-cooled fast breeder reactor. The structure of the flow fluctuation was clarified by means of pressure measurements, laser doppler velocimetry (LDV) and flow visualization. LDV measurements were examined for Reynolds number of 50000. FFT analyses of axial velocities indicate that two kinds of flow fluctuations exist in the present elbow. One is the fluctuation with approximate Strouhal number of 1.0 (3.2 Hz) occurring in a shear flow region. The other is with approximate Strouhal number of 0.5 (1.6 Hz) occurring in the separated and its downstream regions. These fluctuations were also observed by flow visualization. The analyses showed that the stream regime was in good agreement with visualization test results.
Iwamoto, Yukiharu*; Minamiura, Hirotaka*; Sogo, Motosuke*; Yamano, Hidemasa
Nihon Kikai Gakkai Rombunshu, B, 76(765), p.830 - 838, 2010/05
Detailed results of LDV measurement for Reynolds number of 50000 is shown. Frequency analyses of axial velocities indicate that two kinds of flow fluctuations exist in the present elbow. One is the fluctuation with approximate Strouhal number (based on a pipe inner diameter and a bulk velocity) of 1.0 occurring in a shear flow region. The other is with approximate Strouhal number of 0.5 occurring in the separated and its downstream regions. These fluctuations were also observed by flow visualization.
Iwamoto, Yukiharu*; Yasuda, Kazunori*; Sogo, Motosuke*; Yamano, Hidemasa; Kotake, Shoji
Proceedings of 6th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-6) (USB Flash Drive), 6 Pages, 2008/11
Pressure measurement, laser Doppler velocimetry (LDV) and flow visualization were carried out using the 1/10-scale model of a hot leg piping installed in a Japanese sodium-cooled fast breeder reactor. LDV measurement with Reynolds number of 50000 showed the following results: (1) A flow separation was confirmed in the region between 45 degrees from the elbow inlet and 0.3 times of pipe diameter downstream of the elbow. (2) There appeared two kinds of fluctuations in the present study. In the case of Reynolds number of 320000, it was found that the height of the flow separation downstream of the elbow became smaller, since the inertia of the flow became superior to the inverse pressure gradient.
Iwamoto, Yukiharu*; Sogo, Motosuke*; Ezoe, Takanori*; Minamiura, Hirotaka*; Yamano, Hidemasa; Kotake, Shoji
no journal, ,
This study considered an unsteady flow dynamics by measuring velocity distributions and observing the flow in a pipe with a short elbow.
Minamiura, Hirotaka*; Ezoe, Takanori*; Iwamoto, Yukiharu*; Sogo, Motosuke*; Yamano, Hidemasa; Kotake, Shoji
no journal, ,
The LDV measurement allowed us to investigate the time-averaged and time-dependent flow characteristics in a short-elbow pipe flow.
Iwamoto, Yukiharu*; Kondo, Manabu*; Ikeuchi, Hiroki*; Yasuda, Kazunori*; Sogo, Motosuke*; Tanaka, Masaaki; Yamano, Hidemasa
no journal, ,
To clarify the effect of a straight pipe length connecting to the upstream on the elbow flow, the experiment was performed to measure the velocity distribution of the flow with a buffer tank in the upstream from the elbow. The measured data were compared with the previous data in the upstream condition with a fully developed flow.
Kondo, Manabu*; Ikeuchi, Koki*; Iwamoto, Yukiharu*; Yasuda, Kazunori*; Sogo, Motosuke*; Yamano, Hidemasa; Tanaka, Masaaki
no journal, ,
no abstracts in English
Ikeuchi, Koki*; Kondo, Manabu*; Iwamoto, Yukiharu*; Yasuda, Kazunori*; Sogo, Motosuke*; Tanaka, Masaaki; Yamano, Hidemasa
no journal, ,
no abstracts in English
Takai, Yu*; Kondo, Manabu*; Iwamoto, Yukiharu*; Yasuda, Kazunori*; Sogo, Motosuke*; Tanaka, Masaaki; Yamano, Hidemasa
no journal, ,
In the present study, velocity distributions were measured using LDV under 320000 of Reynolds number in an experimental facility, where a swirling flow entered a 90 degree bend.
Kondo, Manabu*; Takai, Yu*; Iwamoto, Yukiharu*; Yasuda, Kazunori*; Sogo, Motosuke*; Yamano, Hidemasa; Tanaka, Masaaki
no journal, ,
In the present study, velocity distributions were measured using LDV under 320000 of Reynolds number in an experimental facility, where a swirling flow entered to a 90-degree bend.
Iwamoto, Yukiharu*; Yasuda, Kazunori*; Sogo, Motosuke*; Tanaka, Masaaki; Yamano, Hidemasa
no journal, ,
LDV measurement has been performed on the swirling inflow with its non-dimensional angular momentum of 0.12 in an elbow whose radius of pipe-axis curvature and inside pipe diameter are the same. Flow-induced-vibration generated in the flow field and elbow has been compared with that of non-swirling inflow to show no difference in non-dimensional frequency.
Ogawa, Shota*; Iwamoto, Yukiharu*; Yasuda, Kazunori*; Sogo, Motosuke*; Yamano, Hidemasa; Tanaka, Masaaki
no journal, ,
no abstracts in English
Iwamoto, Yukiharu*; Ogawa, Shota*; Yasuda, Kazunori*; Sogo, Motosuke*; Tanaka, Masaaki; Yamano, Hidemasa
no journal, ,
Kusuzaki, Ryo*; Murakami, Koichi*; Iwamoto, Yukiharu*; Yamano, Hidemasa; Yasuda, Kazunori*; Sogo, Motosuke*
no journal, ,
Steady and unsteady characteristics was investigated by measuring wall surface pressure at the inner surface of elbow with fast deflected flow into the intrados of the bend, the radius of which is same as the pipe axis curvature radius.