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Hamdani, A.; 安部 諭; 石垣 将宏; 柴本 泰照; 与能本 泰介
Progress in Nuclear Energy, 153, p.104415_1 - 104415_16, 2022/11
被引用回数：3 パーセンタイル：66.21(Nuclear Science & Technology)This paper describes the computational fluid dynamics (CFD) analysis and validation works from the previous experimental study on the natural convection driven by outer surface cooling in the presence of density stratification consisting of air and helium (as a mimic gas of hydrogen). The experiment was conducted in the Containment InteGral effects Measurement Apparatus (CIGMA) facility at Japan Atomic Energy Agency (JAEA). The numerical simulation was carried out to analyze the detailed effect of the cooling region on the erosion of the helium stratification layer. The temporal and spatial evolution of the helium concentration and the gas temperature inside the containment vessel was predicted and validated against the experimental data. In addition, two stratification behaviors that depend on the cooling location were presented and discussed. The CFD simulation confirmed that an upper head cooling caused two counter-rotating vortexes in the helium-rich zone. Meanwhile, the upper half body cooling caused two counter-rotating vortexes in the helium-poor zone. These findings are important to understand the mechanism of the density stratification process driven by natural convection in the containment vessel.
Hamdani, A.; 安部 諭; 石垣 将宏; 柴本 泰照; 与能本 泰介
Proceedings of 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-18) (USB Flash Drive), p.5463 - 5479, 2019/08
The present study introduces thermal mixing and stratification produced by heated air jet located at the bottom level of the containment vessel. The investigation was carried out experimentally and numerically in the large containment vessel called CIGMA (Containment InteGral effects Measurement Apparatus). The experiments were conducted with external surface cooling and various air jet inlet temperatures. The containment cooling was done by flooding the water on the external side of half-upper of a vessel. To identify their influence on the thermal mixing and stratification phenomena, the investigation focuses on mixing convection which occurred in the cooled region of a containment vessel. Temperature distribution and jet velocity were measured by thermocouple and Particle Image Velocimetry (PIV) respectively. Numerical simulation was performed using Computational Fluid Dynamics (CFD) code OpenFOAM to investigate the detail effects of external cooling on the fluid flow and thermal characteristics in the test vessel. CFD results showed a good agreement with experimental data on both temperature and velocity. Both temperature and velocity of hot air jet decayed rapidly downstream jet nozzle. Thermal stratification was observed by visualization of temperature contour maps over a cross-section in the containment vessel. Vigorous mixing was also noticed in the upper region of the containment vessel. Effect of external cooling on mixing and the thermal stratification were presented and discussed.
Hamdani, A.; 安部 諭; 石垣 将宏; 柴本 泰照; 与能本 泰介
no journal, ,
Gas density stratification build-up and its propagation/erosion, which is regarded as a benchmark of hydrogen behavior in a severe accident, were experimentally and numerically studied by using buoyant jet in the containment vessel. The experiments were conducted with external surface cooling and high-temperature air-jet inlet up to 435 degrees Celcius. The CFD simulation was also performed, and the data on temperature and velocity profile were used for the validation.
