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Ebara, Shinji*; Takamura, Hiroyuki*; Hashizume, Hidetoshi*; Yamano, Hidemasa
International Journal of Hydrogen Energy, 41(17), p.7139 - 7145, 2016/05
Times Cited Count：7 Percentile：18.15(Chemistry, Physical)In this study, a flow visualization and pressure measurement were conducted by using an experimental setup including test sections of 1/7-scale models of the cold-leg piping of Japan sodium-cooled reactor with high Reynolds number region up to about one million. Regarding the flow field, flow separation appeared in the intrados of the third elbow. However, the separation region was smaller than that observed in the first elbow in the direction normal to the mean flow and was larger in the streamwise direction. This can be considered because of the swirling flow generated downstream of the second elbow which flowed into the third elbow with a little reduction. From the pressure fluctuation test, it was found that prominent frequencies of the pressure fluctuation appeared at about 0.4 in Strouhal number, which corresponds to a nondimensional frequency, in the region from 0 D to 0.4 D downstream of the elbow outlet, where D is the diameter of the piping. And weak peaks of about 0.7 in Strouhal number were observed in the region far 0.75 D downstream of the outlet.
Ebara, Shinji*; Takamura, Hiroyuki*; Hashizume, Hidetoshi*; Yamano, Hidemasa
Proceedings of 17th International Conference on Emerging Nuclear Energy Systems (ICENES 2015) (CD-ROM), 6 Pages, 2015/10
In this study, a flow visualization and pressure measurement were conducted by using an experimental setup including test sections of 1/7-scale models of the cold-leg piping of Japan sodium-cooled reactor with high Reynolds number region up to about one million. Regarding the flow field, flow separation appeared in the intrados of the third elbow. However, the separation region was smaller than that observed in the first elbow in the direction normal to the mean flow and was larger in the streamwise direction. This can be considered because of the swirling flow generated downstream of the second elbow which flowed into the third elbow with a little reduction. From the pressure fluctuation test, it was found that prominent frequencies of the pressure fluctuation appeared at about 0.4 in Strouhal number, which corresponds to a nondimensional frequency, in the region from 0 D to 0.4 D downstream of the elbow outlet, where D is the diameter of the piping. And weak peaks of about 0.7 in Strouhal number were observed in the region far 0.75 D downstream of the outlet.
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.
Mizutani, Jun*; Ebara, Shinji*; Hashizume, Hidetoshi*; Yamano, Hidemasa
Proceedings of 10th International Topical Meeting on Nuclear Thermal Hydraulics, Operation and Safety (NUTHOS-10) (USB Flash Drive), 12 Pages, 2014/12
In this study, the influence of the inflow condition upon the flow separation and pressure fluctuation characteristic was evaluated by using a 1/7-scale mockup of the cold-leg piping of Japan Sodium-cooled Fast Reactor. The inflow condition to the 3rd elbow was changed from previous studies by varying the distance between the 2nd and 3rd elbows from 6.4D to 9.4D, where D is the pipe diameter. The visualization experiment showed that the flow separation appeared in the intrados of the 3rd elbow as was the case with 6.4D and separated regions became larger than that in the case of 6.4D. This is because a swirling flow observed at the inlet of the 3rd elbow became weaker than that of the case of 6.4D. The frequency analysis of pressure fluctuations showed that gentle but apparent peaks in the power spectral density (PSD) distributions of pressure fluctuations were observed at about 0.4 of the Strouhal number around the separated regions, and this peak value was half of that in the case of 6.4D. In addition, prominent peaks in the PSD distributions were observed at about 0.6 of the Strouhal number in the downstream of the reattachment point in the intrados. The peak value was approximately 3 times larger than that in the case of 6.4D. The results revealed the weakened swirling flow made the separated region larger in the downstream and the pressure fluctuation magnitude stronger.
Takase, Kazuyuki; Ose, Yasuo*; Yoshida, Hiroyuki; Tamai, Hidesada; Kume, Etsuo; Kitamura, Tatsuaki*
Dai-16-Kai Suchi Ryutai Rikigaku Shimpojiumu Koen Yoshishu, 7 Pages, 2002/00
no abstracts in English
Kamata, Hirofumi*; ; *; *
Reza Kenkyu, 24(2), p.30 - 38, 1996/02
no abstracts in English
Tamura, Manabu*; Kondo, Tatsuo
JAERI-M 9948, 27 Pages, 1982/02
Influence of mechanical surface finishing on corrosion was studied with some austenitic heat resisting alloys exposed to the simulated HTGR helium environment. The exposure tests were made at 900 and 1000
C for 500 and 1500h. Contrary to the prediction based on the trend of some conventional experimental results on the oxidation of cold worked material at comparatively low temperatures, severe cold working, e.g. shot-blasting, was found to accelerate oxidation and carburization. Although, in some cases, moderate surface grinding showed results almost comparable to the surface abraded with fine emery papers, most mechanical surface finishing were recognized as to promote oxidation and carburization at 900 and 1000 C in the simulated HTGR helium. The oxide film formed on the ground or shot-blasted specimen tended to spall more easily during cooling after isothermal exposure at 1000C. Based on the metallographic observation mechanisms of the acceleration of oxidation and carburization was discussed. The surface cold work was considered to cause not only enhanced chromium diffusion to the surface but also considerable degree of inhomogeneity of the degree of working in the microscopic scale, resulting in rather rapid oxide build-up and spallation. Some of the surface finishing in practice with severe cold working, thus, were concluded to be harmful to the integrity of HTGR structural components.
Shindo, Masami; Kondo, Tatsuo
JAERI-M 8835, 14 Pages, 1980/04
no abstracts in English
Shindo, Masami; ; Kondo, Tatsuo
JAERI-M 8210, 12 Pages, 1979/04
no abstracts in English
