Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 202

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Simultaneous measurement of dry patch behavior and surface temperature distribution for copper heat transfer surface with deposition layer in nucleate pool boiling

Uesawa, Shinichiro; Ono, Ayako; Koizumi, Yasuo; Shibata, Mitsuhiko; Yoshida, Hiroyuki

Nippon Kikai Gakkai Netsu Kogaku Konfarensu 2018 Koen Rombunshu (USB Flash Drive), 6 Pages, 2018/10

no abstracts in English

Journal Articles

Study on water-vapor two-phase flow behavior in venturi tube

Uesawa, Shinichiro; Horiguchi, Naoki; Shibata, Mitsuhiko; Yoshida, Hiroyuki

Nippon Kikai Gakkai Rombunshu (Internet), 84(859), p.17-00392_1 - 17-00392_10, 2018/03

no abstracts in English

Journal Articles

Application of unstructured mesh-based numerical method to sodium-water reaction phenomenon analysis code SERAPHIM

Uchibori, Akihiro; Watanabe, Akira*; Takata, Takashi; Ohshima, Hiroyuki

Nippon Kikai Gakkai Rombunshu (Internet), 84(859), p.17-00394_1 - 17-00394_6, 2018/03

For assessment of the wastage environment under tube failure accident in a steam generator of sodium-cooled fast reactors, a mechanistic computer code called SERAPHIM calculating compressible multicomponent multiphase flow with sodium-water chemical reaction has been developed. The original SERAPHIM code is based on the finite difference method. In this study, unstructured mesh-based numerical method was developed and introduced into the SERAPHIM code to advance a numerical accuracy for the complex-shaped domain including multiple heat transfer tubes. Validity of the unstructured mesh-based SERAPHIM code was investigated through the analysis of an underexpanded jet experiment. The calculated pressure profile showed good agreement with the experimental data. Numerical analysis of water vapor discharging into liquid sodium was also performed. It was demonstrated that the proposed numerical method could be applicable to evaluation of the sodium-water reaction phenomenon.

Journal Articles

Application of a preconditioned Chebyshev basis communication-avoiding conjugate gradient method to a multiphase thermal-hydraulic CFD code

Idomura, Yasuhiro; Ina, Takuya*; Mayumi, Akie; Yamada, Susumu; Imamura, Toshiyuki*

Lecture Notes in Computer Science 10776, p.257 - 273, 2018/00

A preconditioned Chebyshev basis communication-avoiding conjugate gradient method (P-CBCG) is applied to the pressure Poisson equation in a multiphase thermal-hydraulic CFD code JUPITER, and its computational performance and convergence properties are compared against a preconditioned conjugate gradient (P-CG) method and a preconditioned communication-avoiding conjugate gradient (P-CACG) method on the Oakforest-PACS, which consists of 8,208 KNLs. The P-CBCG method reduces the number of collective communications with keeping the robustness of convergence properties. Compared with the P-CACG method, an order of magnitude larger communication-avoiding steps are enabled by the improved robustness. It is shown that the P-CBCG method is $$1.38times$$ and $$1.17times$$ faster than the P-CG and P-CACG methods at 2,000 processors, respectively.

Journal Articles

Study on pool nucleate boiling heat transfer of suspension liquid with deposits on heat transfer surface

Uesawa, Shinichiro; Koizumi, Yasuo; Shibata, Mitsuhiko; Yoshida, Hiroyuki

Thermal Science and Engineering, 25(2), p.17 - 26, 2017/04

no abstracts in English

Journal Articles

Fundamental validation of fluid-structure thermal interaction simulation code for thermal striping in sodium-cooled fast reactors with parallel triple jets mixing experiments

Tanaka, Masaaki; Kobayashi, Jun; Nagasawa, Kazuyoshi*

Proceedings of OECD/NEA & IAEA Workshop on Application of CFD/CMFD Codes to Nuclear Reactor Safety and Design and their Experimental Validation (CFD4NRS-6) (Internet), 12 Pages, 2016/09

A numerical simulation code named MUGTHES which can deal with conjugate heat transfer problem between the fluid and the structure parts has been developed in order to predict the thermal response in the structure for estimation of the thermal fatigue issue. To perform fundamental validation of the MUGTHES, the benchmark simulation was considered using the experiment of planar triple parallel jets mixing sodium test (PLAJEST). Since it was known by literatures that three representative flow mixing patterns were shown in accordance with the velocity rate of the side jets to the center jet, three typical experimental conditions in the PLAJEST were employed as boundary conditions for the benchmark. Through the numerical simulations, applicability of the large eddy simulation (LES) approach with the standard Smagorinsky model to simulate thermal striping phenomena was confirmed.

Journal Articles

Study on pool nucleate boiling heat transfer of suspension liquid with deposits on heat transfer surface

Uesawa, Shinichiro; Koizumi, Yasuo; Shibata, Mitsuhiko; Yoshida, Hiroyuki

Dai-53-Kai Nihon Dennetsu Shimpojiumu Koen Rombunshu (CD-ROM), 8 Pages, 2016/05

no abstracts in English

Journal Articles

Modeling of initial interaction between the laser pulse and Sn droplet target and pre-plasma formation for the LPP EUV source

Sasaki, Akira; Nishihara, Katsunobu*; Sunahara, Atsushi*; Nishikawa, Takeshi*

Proceedings of SPIE, Vol.9776, p.97762C_1 - 97762C_6, 2016/03

 Times Cited Count:1 Percentile:38.03

For the improvement of efficiency and output of the laser pumped plasma (LPP) extreme ultra-violet (EUV) light source, we present a hydrodynamics model of laser irradiated Sn targets. The model takes liquid/solid to gas transition and mixed phase condition of the flow into account for the calculation of the distribution of the particles produced by the pre-pulse laser irradiation and optimization of the EUV source. Firstly, we investigate the mechanisms of the fragmentation of the target and particle emission, including the effect of the equation of state of Sn, and secondly, an applicable model is proposed based on the analysis.

Journal Articles

Development of numerical estimation method for high cycle thermal fatigue by coupling of fluid-structure thermal interaction simulation and thermal stress analysis

Tanaka, Masaaki; Miyake, Yasuhiro*

Nippon Kikai Gakkai M&M 2015 Zairyo Rikigaku Kanfarensu Koen Rombunshu (Internet), 3 Pages, 2015/11

A prototype coupling method consisting of the fluid-structure thermal interaction simulation code MUGTHES and the structural thermal stress analysis code FINAS with interface program MUFIN has been developed in order to estimate the thermal fatigue in the SFRs. As a fundamental validation of the coupled method, it was applied to the water experiment for thermal mixing phenomena in a T-junction piping system. In the experiment, thermal interaction between the fluid and the structure made of aluminum installed to the branch pipe side wall was considered. Through the numerical simulations, applicability of the coupled method was confirmed.

Journal Articles

SOL-divertor plasma simulations introducing anisotropic temperature with virtual divertor model

Togo, Satoshi*; Takizuka, Tomonori*; Nakamura, Makoto; Hoshino, Kazuo; Ogawa, Yuichi*

Journal of Nuclear Materials, 463, p.502 - 505, 2015/08

 Times Cited Count:8 Percentile:28.72(Materials Science, Multidisciplinary)

A 1D SOL-divertor plasma simulation code introducing the anisotropic ion temperature with virtual divertor model has been developed. By introducing the anisotropic ion temperature directly, the second-derivative parallel ion viscosity term in the momentum transport equation can be excluded and the boundary condition at the divertor plate becomes unnecessary. In order to express the effects of the divertor plate and accompanying sheath implicitly, the virtual divertor model has been introduced which has an artificial sinks of particle, momentum and energy. The virtual divertor model makes the periodic boundary condition available. By using this model, SOL-divertor plasmas satisfying the Bohm condition has been successfully obtained. Also investigated are the dependence of the ion temperature anisotropy on the normalized mean free path of ion and the validity of the approximated parallel ion viscosity for the Braginskii expression and the limited one.

Journal Articles

Benchmark analysis of thermal striping phenomena in planar triple parallel jets tests for fundamental validation of fluid-structure thermal interaction code for sodium-cooled fast reactor

Tanaka, Masaaki; Nagasawa, Kazuyoshi*

Proceedings of 16th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-16) (USB Flash Drive), p.6650 - 6663, 2015/08

For the fundamental validation of fluid-structure thermal interaction code (MUGTHES), numerical simulations for the planar triple parallel jets tests in WAJECO and PLAJEST have been conducted as the benchmark analysis. In comparison between the numerical results and the provided experimental results, thermal mixing process and large-scale eddy structures generated in the triple jets mixing and the relation between temperature fluctuation generation and large-eddy structures were revealed. And also, the attenuation process of temperature fluctuation from the fluid to the structure was indicated.

Journal Articles

Conference report; The 16th International Workshop on Radiative Properties of Hot Dense Matter

Sasaki, Akira; Nishimura, Hiroaki*; Onishi, Naofumi*

Purazuma, Kaku Yugo Gakkai-Shi, 91(2), p.166 - 167, 2015/02

no abstracts in English

Journal Articles

Development of coupled method of fluid-structure thermal interaction simulation and thermal stress analysis for T-junction piping system

Tanaka, Masaaki; Miyake, Yasuhiro*; Karakida, Yasuhisa*

Proceedings of 2nd International Conference on Maintenance Science and Technology (ICMST-Kobe 2014), p.79 - 80, 2014/11

A coupled method of fluid-structure thermal interaction simulation and thermal stress analysis has been developed through the interface program to carry out direct numerical estimation of the thermal fatigue. The prototype method was applied to the thermal mixing phenomena in T-junction Piping System.

Journal Articles

Study of global wall saturation mechanisms in long-pulse ELMy H-mode discharges on JT-60U

Takenaga, Hidenobu; Nakano, Tomohide; Asakura, Nobuyuki; Kubo, Hirotaka; Konoshima, Shigeru; Shimizu, Katsuhiro; Tsuzuki, Kazuhiro; Masaki, Kei; Tanabe, Tetsuo*; Ide, Shunsuke; et al.

Nuclear Fusion, 46(3), p.S39 - S48, 2006/03

 Times Cited Count:18 Percentile:45.37(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Modeling of impurity transport in high density plasma with highly enhanced radiation loss on JT-60U

Takenaga, Hidenobu; Asakura, Nobuyuki; Kubo, Hirotaka; Konoshima, Shigeru; Nakano, Tomohide; Porter, G.*; Rognlien, T.*; Rensink, M.*

Journal of Plasma and Fusion Research SERIES, Vol.7, p.35 - 39, 2006/00

no abstracts in English

Journal Articles

Shape optimization using parameter-survey-type parallel adjoint variable method

Shinohara, Kazunori; Okuda, Hiroshi*; Nakajima, Norihiro; Ida, Masato

Nippon Kikai Gakkai Dai-18-Kai Keisan Rikigaku Koenkai Koen Rombunshu, p.561 - 562, 2005/11

To obtain optimal designed shape effectively, the 3D shape optimization system of adjoint variable method is developed. The adjoint valiable method is based on the Lagrange multiplier method (a conditional variational principle), and consists of the state equation, the adjoint equation and the sensitivity equation. The equations for decreasing the fluid drag of surface under a constant volume condition are formulated. To solve the equations effectively, the compressed-matrix storage mode and the data passing system are implemented by using HPCMW. By using the 3D shape optimization system, the surface force of shape can be reduced about 24%.

Journal Articles

Numerical visualization of herted liquid film flow behavior around a spacer in a narrow channel

Kume, Etsuo; Kitamura, Tatsuaki*; Takase, Kazuyuki; Ose, Yasuo*

Kashika Joho Gakkai-Shi, 25(Suppl.2), p.369 - 370, 2005/10

no abstracts in English

Journal Articles

Two disordered phases; Macroscopic fluid-liquid phase separation in phosphorus

Katayama, Yoshinori

Nippon Butsuri Gakkai-Shi, 60(6), p.456 - 460, 2005/06

By means of in-situ high-temperature and high-pressure experiment, we found two distinct structures of molten phosphorus, one is a molecular fluid and the other is a polymeric liquid, and an abrupt and reversible structural transformation between them at about 1 GPa. Further investigations revealed that the two structures have different densities and they separate macroscopically during the transformation. These results support a view that this change is an extremely rare example of a first-order phase transition between two stable disordered phases besides liquid-gas transition.

Journal Articles

Towards coupling arbitrary software on the Japanese ITBL Grid infrastructure using MpCCI

Hazama, Osamu; Nakajima, Norihiro

Proceedings of 6th MpCCI User Forum, p.76 - 77, 2005/05

In order to accurately solve complex physical phenomena, interactions of various phenomena must be considered, which makes simulations multi-disciplinary. We have been developing a virtual nuclear reactor simulator on the ITBL Grid infrastructure in order to assess the safety of the nuclear reactors. This simulator system allows for numerical experiments on the full-scale and fully operational virtual nuclear reactors which is not possible in real-life experiments. In order to clarify various complex physical phenomena within the reactors, multi-disciplinary simulations, which are computationally demanding, are required. We have been developing a software to allow concurrent use of arbitrary combination of hardware and software to realize a multi-disciplinary simulation system on the ITBL. We have used STAMPI, developed by CCSE/JAERI, and MpCCI, developed by Fraunhofer SCAI, to construct the system. The system is now functional on the ITBL and will be introduced.

Journal Articles

Chaos analysis from simulations of plasma turbulence driven by electron/ion temperature gradient

Matsumoto, Taro; Kishimoto, Yasuaki; Li, J.*

Denki Gakkai Purazuma Kenkyukai Shiryo (PST-05-17), p.83 - 86, 2005/03

no abstracts in English

202 (Records 1-20 displayed on this page)