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Yamano, Hidemasa; Tanaka, Masaaki; Ebara, Shinji*; Hashizume, Hidetoshi*
Proceedings of 27th International Symposium on Transport Phenomena (ISTP-27) (USB Flash Drive), 8 Pages, 2016/09
In this study, Unsteady Reynolds Averaged Navier-Stokes equation (U-RANS) approach with the Reynolds Stress Model using commercial CFD code has been applied to the flow through triple short-elbows under a high Re (1.0
10
). This numerical simulation has utilized a 1/7 scaled water experiment of the advanced SFR cold-leg piping in order to investigate the flow structure in a three-dimensionally connected triple elbows. As a result, applicability of the U-RANS numerical simulation method was confirmed by comparison between the numerical and experimental results under Re = 1.010 condition. The simulation has also shown that flow fields in the 1st elbow was different from that in the 2nd elbow and pressure fluctuation in the 2nd elbow was slightly larger than that in the 1st elbow because of the presence of their large vortex flow structure. This large vortex was generated due to a short distance between two elbows. On the other hand, the flow structure in the 3rd elbow was similar to that in the 1st elbow because the swirling flow formed in the 2nd elbow was alleviated in the 3rd elbow inlet which was located long way away from the 2nd elbow.
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.
Yamano, Hidemasa; Xu, Y.*; Sago, Hiromi*; Hirota, Kazuo*; Baba, Takeo*
Proceedings of 2016 International Congress on Advances in Nuclear Power Plants (ICAPP 2016) (CD-ROM), p.1029 - 1038, 2016/04
This study conducted the flow-induced vibration evaluation of the primary hot-leg piping in the demonstration reactor design of advanced loop-type sodium-cooled fast reactor in order to confirm the integrity of the piping. Following the description of the primary hot-leg piping design and a design guideline of the flow-induced vibration evaluation, this paper describes mainly the flow-induced vibration evaluation and thereby the integrity assessment. In the fatigue evaluation for the flow-induced vibration, the pipe stresses considering the stress concentration factor and so on, at representative locations were less than the design fatigue limit. Therefore, this evaluation confirmed the integrity of the primary hot-leg piping in the demonstration reactor.
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.
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.
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.
Yamano, Hidemasa; Kaneko, Tetsuya*; Aizawa, Kosuke; Tanaka, Masaaki; Ebara, Shinji*; Hashizume, Hidetoshi*
Proceedings of 9th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-9) (CD-ROM), 10 Pages, 2014/11
In this study, Unsteady Reynolds Averaged Navier-Stokes equations (U-RANS) approach with the Reynolds Stress Model using a commercial computational fluid dynamics code has been applied to the flow through single and double short-elbows under a high Reynolds number condition (1.010). This numerical simulation has utilized a 1/7 scaled water experiment simulating the JSFR cold-leg piping in order to investigate the flow pattern in a three-dimensionally connected double elbow. As a result, validity and applicability of the U-RANS numerical simulation method were confirmed by comparison between the numerical and experimental results. The simulation has also shown that unsteady flow fields including vortex structures in the 1st elbow were very different from that in the 2nd elbow. This is because horseshoe vortexes generated in the 1st elbow downstream enter sideways the 2nd elbow. In addition, the simulation has indicated that the influence of distance between two elbows in the double elbow flow addressed in this paper was small.
Tsukimori, Kazuyuki; Furuhashi, Ichiro*
JNC TN9400 2000-049, 93 Pages, 2000/03
JNC-TN9400-2000-049.pdf:2.82MB
lt is one of the important key points to reduce thermal stress of the primary piping system in the design of sodium coolant loop-type FBR plants. The objectives of this study are to understand the characteristics of the thermal stresses in the simple S-shaped hot leg piping systems which run from the outlet nozzle of the reactor vessel (R/V) to the inlet nozzle of the intermediate heat exchanger (IHX), and to propose some recommendable routings of piping systems. Results are summarized as follows. (1)Generally, the thermal stresses in elbows are severer than those at nozzles. The tendency was observed that the stress in elbow decreases with the increase of the distance between the outlet nozzle of R/V and the inlet nozzle of IHX and also the distance between the outlet nozzle of R/V and the liquid surface level. (2)lt is expected to reduce thermal stresses in elbow to big extent by adopting super 90 degree elbows. Therefore, in these cases the dimension region which satisfies the allowable stress is broad compared with that in the case of the conventional 90 degree elbow. (3)The stress estimations in elbow based on 'MITl notice No.501' become excessively large compared with the results by FEA using shell elements, when the maximum stress occurs at the end of elbow. ln these cases, the estimation can be rationalized by replacing the maximum stress by the mean of stresses at the end and at the middle of the elbow. (4)Two routings with 105 degree elbows are recommended. 0ne has the advantage from the view point of reduction of length of pipe and the other does from the view point of reduction of thermal stresses, compared with the routing with 90 degree elbows.
JNC TN9400 2000-008, 323 Pages, 2000/02
JNC-TN9400-2000-008.pdf:25.2MB
This rport presents numerical results on theemal striping characteristics at a tee junction of LMFBR coolant pipe, carried out using a direct numerical simulation code DINUS-3. In the numerical investigations, it was considered a tee junction system consisted of a main pipe (1.33 cm
) with a 90
elbow and a branch pipe, and four parameters, j.e., (1)diameter ratio 
between both the pipes, (2)flow velocity ratio 
between both the pipes, (3)angle 
between both the pipes, and (4)Reynolds number Re. From the numerical investigations, the following characteristics were obtained: (1)According to the decreasing of the diameter ratio, significant area of second-order moments was expanded in the fixed condition of =1.0. (2)Significant second-order moments area was expanded for the increasing of the flow velocity ratio specified by varying of the main pipe velocity in the case of a = 1.0 constant condition. 0n the other hand, the area was expanded for the decreasing of the velocity ratio defined by varying of the branch pipe velocity in the case of a = 3.0 constant condition. (3)Maximum second-order moments values were generated in the case of = 180 due to the influence of interactions between main pipe flows and jet flows from the branch pipe. (4)According to the increase of Reynolds number, significant area of second-order moments was expanded due to the activation of turbulence mixing in the main pipe.
; *; Furuhashi, Ichiro*
PNC TN9410 88-147, 215 Pages, 1988/09
The present study includes the analytical work for of the stable crack growth of the finite plate with semi-elliptical surface defect by creep-fatigue loadings, and of the crack opening area for presumed leakage of cloolant to be considered in safety assessment. The objective of this study is to develop the basic inelastic fracture mechanics to the level in which the integrity of basic components, plate, vessel, piping, and so on, with crack would be able to be assessed analytically. CANIS code developed last year was used to analize the J integral for fatigue crack growth and J' integral for creep crack growth of SUS 304 plates with various shapes of semi-elliptical surface cracks at 500 C, then those distributions were arranged from the view point of crack growth assessment. An appricable range of these data is 
1.5 Sm of fatigue cycle and hold time of 10
8,000 hr creep. 0nly secondary stress including membrane, bending and combination of these stresses were considered in the data base. Evaluation of elbow with 42
diameter and 20.6mm thickness considered in the design of large loop type FBR were achieved based on the data base. Then calculated through wall crack lengths were applied to the calculation of opening areas of 42 elbow subjected of internal pressure of 2 atg and in plane bending moment corresponding to stress level of 1.5Sm. The results are (1)A numbers of cycles at penetration are 6,250 for membrane stress and 30,520 for bending stress in the case of fatigue, and 303 for memberane and 1,534 for bending in the case of creep-fatigue. (2)opening area against internal pressure is larger than that against bending moment, and is about 0.5mm
. (3)maximum leak rate from the opening area is about 23 
/hr. The level up of analytical method for stable crack growth was almost accomplished. In the near future, the experimental study would be needed for validation of this method.
Ono, Ayako; Tanaka, Masaaki; Kobayashi, Jun; Kamide, Hideki
no journal, ,
no abstracts in English
Xu, Y.*; Sago, Hiromi*; Hirota, Kazuo*; Baba, Takeo*; Yamano, Hidemasa
no journal, ,
Structural integrity evaluation has been carried out for a hot-leg pipe due to random vibration induced by turbulence of pipe flow using "proposed guideline of flow-induced vibration evaluation for the primary hot-leg piping in sodium-cooled fast reactor", which has reflected the R&D results of the flow-induced vibration for a large-diameter piping. This gave the prospect of integrity of the primary hot-leg piping in the demonstration fast reactor.
Mizutani, Jun*; Ebara, Shinji*; Hashizume, Hidetoshi*; Yamano, Hidemasa
no journal, ,
In a cold-leg piping of the primary cooling system of next-generation sodium-cooled fast reactors, pressure fluctuations induced by vortex shedding are expected as well as the inflow of strong swirling flow and the formation of complicated turbulent flow. This study experimentally investigated flow fields, in particular time-averaged fields, inside the elbow and in its downstream under various swirling inflows using a swirling flow generator.
Hosoda, Takatoshi*; Mizutani, Jun*; Ebara, Shinji*; Hashizume, Hidetoshi*; Yamano, Hidemasa
no journal, ,
In a cold-leg piping of the primary cooling system of next-generation sodium-cooled fast reactors, inflow condition from the intermediate heat exchanger to the piping is swirling flow which was shown by numerical simulations. This experimental study investigated pressure fluctuation characteristics under the condition close to the reactor condition by measuring pressure fluctuations in case of the swirling inflow using a 1/7 scale model.
Mizutani, Jun*; Ebara, Shinji*; Hashizume, Hidetoshi*; Yamano, Hidemasa
no journal, ,
This study evaluated experimentally the effect of influence of the inflow condition upon the flow field in the cold leg piping of the primary cooling system of a sodium-cooled loop-type fast reactor by using a swirling flow generator. Flow visualization with the two-dimensional particle image velocimetry was conducted to reveal the velocity fields of the flow in the piping, especially fluctuating velocity fields, and the results were compared to those obtained from the fully-developed turbulent inflow case. The experiment showed that the there appeared long-period vortices shedding with weak periodicity from the intrados of the 1st elbow instead of steady vortices shedding from flow separation region. In the 2nd elbow, the periodicity of fluctuating velocities were not largely different from those obtained in the fully-developed turbulent inflow case. The downstream of the 2nd elbow was not largely affected by the inflow condition.
Abe, Masato; Watakabe, Tomoyoshi; Moriizumi, Makoto*; Tsukimori, Kazuyuki
no journal, ,
The seismic load which occurs to the equipment and piping at the time of an earthquake in nuclear power plants has the various conditions. As for the load direction, it is not certain when earthquake condition. In this paper, a result of analytical evaluation of impact on structural strength of a thin wall elbow is reported, for the purpose of contribute to structural integrity evaluation of the thin wall piping.
Ebara, Shinji*; Mizutani, Jun*; Hashizume, Hidetoshi*; Yamano, Hidemasa
no journal, ,
In this study, the flow fields with the swirling flows as the inlet condition were analysed mainly in terms of fluctuating velocity fields. Experimental results just downstream of the first elbow revealed that the inlet swirling flow blocked the forming of Dean vortices and steady flow separation in the intrados of the elbow. This led dissipation of the prominent vortices structure in the flow fields, which is seen in those with a fully-developed turbulence as the inlet condition. However, intermittent flow separations appear and these cause the vortices structures with weak periodicity. From experimental results about the second and the third elbows, it was found that more than one periodic motion can be seen in the circumferential direction. This can be interpreted as the interaction between the swirling flow originated from the inlet condition and the intrinsic flow generated in the elbow piping.
