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Yamano, Hidemasa; Tanaka, Masaaki; Iwamoto, Yukiharu*
Proceedings of ASME-JSME-KSME Joint Fluids Engineering Conference 2015 (AJK 2015-FED) (USB Flash Drive), p.231 - 240, 2015/07
This paper intends to validate the numerical simulation tool, the U-RANS approach with the Reynolds Stress Model. It is a commercial computational fluid dynamics code using single short-elbow in the 1/10 and 1/3 scale water experiments simulating JSFR hot-leg piping. The numerical results agreed with their experimental data for time-averaged velocity distributions, flow field visualization, and power spectral densities of pressure fluctuation. U-RANS numerical simulation tool validated single short elbow flow applicable. Also, unsteady flow fields in the show elbow flow with a cyclic secondary flow and the subsequent horse shoe vortex were shown. The numerical simulation results with or without the IHX plenum at the outlet from the effect of the outlet condition did not show significant difference in terms of the time-averaged velocity distribution, pressure fluctuation power spectral density. Hence the effect of the outlet condition is assumed to be negligibly small.
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*; Yamano, Hidemasa
Journal of Fluid Science and Technology (Internet), 9(3), p.JFST0055_1 - JFST0055_13, 2014/09
Wall pressure measurements were conducted for a 90 degree elbow of which the axis curvature coincided with its inner diameter (125 mm). Results showed that distributions of fluctuating normalized pressures obtained here and those made by Shiraishi et al. (2006) for the Reynolds number of 3,250,000 coincided within 0.02 of the dynamic pressure. The peak intensity having the Strouhal number of 0.5 was quantitatively in accordance with that of the data obtained in the experimental setup that Shiraishi et al. used (Yamano et al., 2011), suggesting that the law of dynamical similarity could be applied with regard to this oscillation. Cross correlations of pressure fluctuations showed that the pressure fluctuation having the Strouhal number of 0.5 propagated as a planar wave with the bulk velocity.
Iwamoto, Yukiharu*; Yamano, Hidemasa
Proceedings of 4th International Conference on Jets, Wakes and Separated Flows (ICJWSF 2013) (CD-ROM), 6 Pages, 2013/09
Wall pressure measurements were made for a 90 degree elbow of which the axis curvature coincided with its inner diameter (125 mm). Reynolds numbers examined were 3.2 
10
and 5.0 10. Results showed that distributions of fluctuating normalized pressures obtained here and the result made by Shiraishi et al. for the Reynolds number of 3.25 10
coincided one another within 0.02 of the dynamic pressure. The peak spectrum with the Strouhal number of 0.5 could be found in the inner region downstream of the elbow. They correspond to the vortex shedding from the boundary layer developed in the inner and aft part of the elbow. The peak intensity having the Strouhal number of 0.5 quantitatively coincided with the data obtained in the experimental setup that Shiraishi et al. used, suggesting that the law of dynamical similarity could be applied with regard to this oscillation.
Sakai, Takaaki; Yamano, Hidemasa; Tanaka, Masaaki; Ono, Ayako; Ohshima, Hiroyuki; Kaneko, Tetsuya*; Hirota, Kazuo*; Sago, Hiromi*; Xu, Y.*; Iwamoto, Yukiharu*; et al.
Proceedings of 15th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-15) (USB Flash Drive), 13 Pages, 2013/05
The development of flow-induced vibration evaluation methodology has reached a milestone that separate-effect experimental data under a high Reynolds number regime including swirl and deflected inflow conditions are available for the validation of the methodology. On the other hand, technical standards are desirable to be documented for designers of sodium-cooled fast reactors. From such a background, the documentation of a flow-induced vibration design guideline has been made for the hot-leg piping of Japan sodium-cooled fast reactor. This paper describes the design guideline of the flow-induced vibration evaluation methodology, which has been informed from main separate-effect experiments, as well as supplemental interpretation for the guideline.
Iwamoto, Yukiharu*; Kondo, Manabu*; Minamiura, Hirotaka*; Tanaka, Masaaki; Yamano, Hidemasa
Journal of Fluid Science and Technology (Internet), 7(3), p.315 - 328, 2012/08
LDV measurements in a 90 degree elbow of which the curvature radius coincides with its inner diameter were examined for the cases of inflow from a long pipe, short pipe and swirl generator. Ensemble averaged flow distribution at the Reynolds number of 320000 based on the inner pipe diameter and bulk velocity shows that shortening the upstream pipe length to 4.9D from 10D induces the flow separation downstream of the elbow.
Iwamoto, Yukiharu*; Kondo, Manabu*; Ogawa, Shota*; Tanaka, Masaaki; Yamano, Hidemasa
Nihon Kikai Gakkai Rombunshu, B, 78(792), p.1383 - 1387, 2012/08
LDV measurements in a 90 degrees elbow which curvature radius coincides with the diameter have been conducted. This paper especially focuses on a result of the deflected inflow, comparing with a result of the short pipe. The result shows that the deflected inflow reinforced a convex velocity distribution occurring near the curvature inside in the downstream region, concluding that the deflected inflow promotes the secondary flow of Prandtl's first kind in the elbow. Its Strouhal number increases to 0.6 from 0.5, compared with the short pipe case. Results of frequency analyses are also shown for other cases that we have been examined. Dominant Strouhal numbers in most of the cases become 0.5, except for 0.6 in cases of the inflow from the long pipe and deflector. This frequency shift might be related with the boundary layer size and the local flow velocity, since the corresponding fluctuation is caused by vortex shedding from the boundary layer at the elbow inside.
Tanaka, Masaaki; Sago, Hiromi*; Iwamoto, Yukiharu*; Ebara, Shinji*; Ono, Ayako; Murakami, Takahiro*; Hayakawa, Satoshi*
Nihon Kikai Gakkai Rombunshu, B, 78(792), p.1392 - 1396, 2012/08
A study on flow induced vibration in the primary cooling system of Japan Sodium cooled Fast Reactor (JSFR) consisting of large diameter pipe and pipe elbow with short curvature radius ("short-elbow") has been conducted. Flow-induced vibration in the short-elbow is an important issue in design study of JSFR, because it may affect to structural integrity of the pipe. In this paper, unsteady flow characteristics in the JSFR short-elbow pipe related to the large-scale eddy motion were estimated based on knowledge from existing studies for curved pipes and scaled water experiments and numerical simulations for the JSFR hot-leg piping.
Yamano, Hidemasa; Tanaka, Masaaki; Ono, Ayako; Murakami, Takahiro*; Iwamoto, Yukiharu*; Yuki, Kazuhisa*; Sago, Hiromi*; Hayakawa, Satoshi*
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles (FR 2009) (CD-ROM), 12 Pages, 2012/00
This paper describes the current status of flow-induced vibration evaluation methodology development for primary cooling pipes in JSFR, in particular emphasizing on recent R&D activities that investigate unsteady elbow pipe flow. The experiment using the 1/3-scale test section was performed to investigate the effect of swirl flow at the inlet. Although the flow separation region was distorted at the downstream from the elbow, the experiment clarified that the effect of swirl flow on pressure fluctuation onto the pipe wall was not significant. The simulation revealed that Reynolds number scarcely affects flow patterns and flow velocity distributions.
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
Yamano, Hidemasa; Tanaka, Masaaki; Murakami, Takahiro*; Iwamoto, Yukiharu*; Yuki, Kazuhisa*; Sago, Hiromi*; Hayakawa, Satoshi*
Journal of Nuclear Science and Technology, 48(4), p.677 - 687, 2011/04
This paper describes the current status of flow-induced vibration evaluation methodology development for primary cooling pipes in Japan Sodium-cooled Fast Reactor (JSFR), in particular emphasizing on recent R&D activities that investigate unsteady elbow pipe flow.
Iwamoto, Yukiharu*; Sogo, Motosuke*; Aizawa, Kosuke; Nakanishi, Shigeyuki*; Yamano, Hidemasa
JAEA-Research 2010-009, 58 Pages, 2010/06
JAEA-Research-2010-009.pdf:31.02MB
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*; Yamano, Hidemasa
Research on Turbulence, p.103 - 107, 2008/03
This study clarified unsteady flow characteristics by flow observation and flow-distribution measurement in a short-elbow pipe.
Tanaka, Masaaki; Murakami, Satoshi; Hibara, Hideki*; Iwamoto, Yukiharu*
no journal, ,
no abstracts in English
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*; Minamiura, Hirotaka*; Aoyama, Yoshiyuki*; Murakami, Koichi*; Yamano, Hidemasa; Kotake, Shoji
no journal, ,
Velocity distributions have been measured by an LDV under 50000 of Reynolds number to grasp the flow characteristics in a hot-leg piping with a single elbow.
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.
