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이송되는 컵 내부의 자유 표면의 거동 특성에 대한 수치해석
홍태협(Tae Hyub Hong),채희문(Hee Moon Chae),김창녕(Chyang Nyung Kim) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
A manipulator is operated for the motion of mechanical hands or arms by mechanical mechanism. When a cup including liquid inside is shifted by a manipulator, it is important to know how a free surface of the liquid moves. In this study, non-dimensional parameters have been found that affect the rise of the free surface in a cup moving with constant acceleration. The non-dimensional parameters are the dimensionless time, the ratio of inertia effect to vicous effect (Reynolds number), aspect ratio of the liquid inside the cup and acceleration ratio (Froude number). Through this study, the height of the free surface rise in a cup has been predicted. Generally the maximum rise of the free surface is dependent on the Reynolds number and Froude number strongly, but on the aspect ratio weakly. But the influence of the aspect ratio on the maximum rise of the free surface in not negligible in the range 10 < Re < 100.
Tae Hyub Hong(홍태협),Sang Won Lee(이상원),Hyeong Taek Kim(김형택) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
In the present study, a Computational Fluid Dynamics (CFD) analysis of the coolant flow in the containment pool is carried out and debris transportation is evaluated using the Lagrangian particle tracking method. The containment pool flow is simulated as a single-phase model and a two-phase model. In the single-phase model, the boundary representing a free surface is set to be a slip boundary condition. The two phase model uses Volume of Fluid (VOF) method. The transport of debris is calculated after achieving a steady state in the simulation of each model. The simulation results show that flow patterns are similar in both models, and the velocity magnitude calculated from the VOF model is less than that calculated from the single-phase model, in general.
원자로 외벽 냉각에서의 상변화 열전달 및 이상유동에 대한 수치해석
홍태협(Tae-Hyub Hong),최유정(Yu Jung Choi),이상원 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10
The hypothetical scenario of a severe accident with core meltdown and formation of a melt pool in the lower plenum of the reactor pressure vessel (RPV) can result in the failure of the RPV and the discharging of the melt to the containment. One accident management strategy could be the stabilization of the RPV by cooling the outside vessel wall with water. This is the concept of IVR-ERVC. The purpose of this study offers detailed information on complex thermal hydrodynamic phenomena, including boiling and two-phase flows, in APR1400 for IVR-ERVC. The thermal hydrodynamic phenomena are simulated using a computational fluid dynamics (CFD) technique with a phase change heat/mass transfer approach for boiling and the volume of fluid (VOF) approach for two-phase flows. The simulation results give a better understanding on the natural circulation mechanism of cooling water, boiling and two-phase flows in this system. Also, this study provides quantitative data such as natural circulation flow rates and heat transfer coefficients in different cooling water temperatures.
OPR1000 원자로 격납건물 내 중대사고 시 수소 및 증기 거동에 대한 CFD 해석
홍태협(Tae Hyub Hong),최청열(Choengryul Choi),김형택(T. H. Kim) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10
Hydrogen could be generated by an active reaction of the fuel-cladding and the steam in the reactor pressure vessel during a hypothetical severe accident in a nuclear power plant (NPP). In such situation, the generated hydrogen is released together with steam into the containment. In order to mitigate hydrogen hazards which could possibly occur in the NPP containment, a hydrogen mitigation system (HMS) is usually adopted, such as hydrogen igniters and passive autocatalytic recombiners (PAR). In this study, an analysis of the hydrogen and steam behavior has been numerically performed using fully 3-dimensional computational fluid dynamics (CFD) technique, during a total loss of feed water (LOFW) accident in the OPR1000 containment. During the accident, a huge amount of hot water, steam, and hydrogen are released into the containment. The possibilities of flame acceleration and a transition from deflagration to detonation (DDT) are evaluated by using the Sigma?ambda criteria.
이송되는 컵 형상에 따른 자유표면의 거동 특성에 관한 연구
김윤선(Yun Sun Kim),홍태협(Tae Hyub Hong),김창녕(Chang Nyung Kim) 대한설비공학회 2009 대한설비공학회 학술발표대회논문집 Vol.2009 No.-
A manipulator is operated for the motion of mechanical hands or arms. When a cup including liquid inside is shifted by a manipulator, it is important to know how a free surface of the liquid moves. In this study, non dimensional parameters have been found that affect the rise of the free surface in a cup moving with constant acceleration. The non-dimensional parameters are the dimensionless time, the ratio of inertia effect to viscous effect (the Reynolds number), aspect ratio of the liquid inside the cup and the acceleration ratio (the Froude number). Through this study, the height of the free surface rise in a cup has been predicted and the detailed velocities in the liquid have been examined. Generally, the maximum rise of the free surface is dependent on the Reynolds number and Froude number strongly, but on the aspect ratio weakly. However, the influence of the aspect ratio on the maximum rise of the free surface is not negligible in the range of 10 < Re < 100.
김윤선(Yun Sun Kim),홍태협(Tae Hyub Hong),김창녕(Chang Nyung Kim) 한국유체기계학회 2008 유체기계 연구개발 발표회 논문집 Vol.2008 No.-
A manipulator is operated for the motion of mechanical hands or arms. When a cup including liquid inside is shifted by a manipulator, it is important to know how a free surface of the liquid moves. In this study, non-dimensional parameters have been found that affect the rise of the free surface in a cup moving with constant acceleration. The non-dimensional parameters are the dimensionless time, the ratio of inertia effect to viscous effect (the Reynolds number), aspect ratio of the liquid inside the cup and the acceleration ratio (the Froude number). Through this study, the height of the free surface rise in a cup has been predicted and detailed velocities in the liquid have been examined. Generally the maximum rise of the free surface is dependent strongly on the Reynolds number and Froude number strongly, but on the aspect ratio weakly. But the influence of the aspect ratio on the maximum rise of the free surface in not negligible in the range of 10<Re<100.
이송되는 컵 내부의 자유 표면의 거동 특성에 대한 수치해석
김윤선(Yun Sun Kim),홍태협(Tae Hyub Hong),김창녕(Chang Nyung Kim),임성수(Sung Soo Rhim) 대한설비공학회 2009 설비공학 논문집 Vol.21 No.7
A manipulator is operated for the motion of mechanical hands or arms. When a cup including liquid inside is shifted by a manipulator, it is important to know how a free surface of the liquid moves. In this study, non dimensional parameters have been found that affect the rise of the free surface in a cup moving with constant acceleration. The nondimensionalparameters are the dimensionless time, the ratio of inertia effect to viscous effect (the Reynolds number), the aspect ratio of the liquid inside the cup and the acceleration ratio (the Froude number). Through this study, the height of the free surface rise in a cup has been predicted and the detailed velocities in the liquid have been examined. Generally, the maximum rise of the free surface is dependent on the Reynolds number and Froude number strongly, but on the aspect ratio weakly. However, the influence of the aspect ratio on the maximum rise of the free surface is not negligible in the range of 10 < Re < 100.