• Proceedings of the SAREK Conference
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• 2007.06a
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• pp.97-97
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• 2007

• Nuclear Engineering and Technology
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• v.50 no.5
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• pp.717-723
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• 2018

Thermal analysis of accident conditions is an important problem during safety assessment of the dry spent nuclear fuel storage facilities. Thermal aspects of accident conditions with channel blockage of ventilated storage containers are considered in this article. Analysis of flow structure inside ventilated containers is carried out by numerical simulation. The main mechanisms of heat and mass transfer, which take part in spent nuclear fuel cooling, were detected. Classification of accidents on the basis of their influence on the maximum temperatures inside storage casks is proposed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.6
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• pp.658-665
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• 1998

This paper investigates local exhaust effectiveness in a room with a supply and an exhaust slots on the ceiling. The mean age of air is an indicator of supply effectiveness, while the mean residual life time can be used as an indicator of exhaust effectiveness. The distribution of local mean residual life time in a space is calculated by four different numerical procedures. The reverse-flow calculation method has been proved to show quite accurate results while it can save considerable amount of computation time and efforts, compared to the method by its original definition. It is concluded that the diffusion term in the equation of mean residual life time can be neglected. The spatial and temporal diffusion characteristics of the contaminant are also discussed.

• Journal of computational fluids engineering
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• v.11 no.4 s.35
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• pp.26-31
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• 2006

In the present study, a numerical simulation of the subway carriage fire is performed to determine the more effective operation of Trackway Exhaust System(TES) in underground stations. The four types of possible TES operation (OSUS, OSUE, OEUS and OEUE) is simulated and compared their removal capability of smoke and hot temperature for the carriage fire of 2MW. From the results, the distribution of temperature and smoke concentration is more dependent on the operation of fans located at upper side of the platform than those at lower side. It is also found from the results that for more efficient smoke control, the fans at upper side of the platform should be operated as an exhaust system. Whereas the fans at lower side can be operated as a supply system to aid upper exhaust fans.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1619-1625
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• 2007

This paper deals with the heat transfer characteristics due to a fire of train standing at under-ground station. In order to analyze the fluid characteristics at under-ground station, the governing equation was assumed to be steady-state, incompressible and turbulent fluid model. The commercial Fluent ver. 6.0 was used to solve the above numerical problem. Through the numerical analysis, fluid path-line, temperature distribution and $CO_2$ density distribution are demonstrated for three kinds of cases. As a conclusion of the study, a scenario for operation of ventilation fan in a fire is proposed.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2000.11a
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• pp.212-216
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• 2000

어떤 특정한 환경과 상황을 가상적으로 모의함으로써 그 환경에 있는 사람이 마치 실제적인 환경 또는 상황과 상호 작용을 하고 있는 것처럼 만들어 주는 진보된 기술을 가상현실(virtual reality) 이라고 한다. 가상현실을 실현하기 위해서는 주변의 영상, 음향, 운동감, 열환경, 후각환경 등이 실제처럼 제시되어야 한다. 본 연구에서는 이중 후각환경의 제시를 위하여 급기 및 배기 위치에 따른 향 농도의 분포를 수치해석적으로 예측한다. 수치해석 결과는 VR 영상관의 향 배기 시스템의 설계 자료로 활용된다.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1740-1746
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• 2008

The present study performed numerical investigation to analyze the smoke behavior in the rescue station by using the commercial CFD code (FLUENT Ver 6.3). The present study adopted a 10MW ultrafast mode for simulation, and it also used the MVHS(Modify Volumetric Heat Source) model modified from the original VHS(Volumetric Heat Source) model in order to treat the product generation and the oxygen consumption under the stoichiometric state. In addition, the present simulation includes the species conservation equation for the materialization of heat source and the estimation of smoke movement. From the results, the smoke flows are moving along the ceiling because of thermal buoyancy force and as time goes, the smoke gradually moves downward at the vicinity of the entrance. Moreover, without using ventilation, it is found that the smoke flows no longer spread across the cross-passages because the pressure in the non-accident tunnel is higher than that in the accident tunnel.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2001.05a
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• pp.63-68
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• 2001

In wide angle diffuser, the cross-sectional area increases so rapidly that separation can be avoided only by using boundary layer control. In this study, an experimental and numerical study is performed on performance of a diffuser with guide damper. A series of measurements were carried out to investigate the characteristics of diffuser for different divergence angle(${\phi}=7^{\circ}, \;10.5^{\circ}\;and\; 14^{\circ}$) of guide damper and angle of ${\phi}=10.5^{\circ}$ was through to be the best among three cases. Judging from the results, guide damper can be used as an effective means of improvement for diffuser performance.

• Fire Science and Engineering
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• v.30 no.2
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• pp.68-74
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• 2016

In semi-transverse ventilation system applied for road tunnel, adjustment of the port opening ratio is an essential part for uniform airflow rate per unit length over the entire tunnel. However, it has not been considered decently throughout the design process and operating of the tunnel. Therefore, in this study, we developed a program for the calculation of the opening size ratio of supply or exhaust port in transverse ventilation system and carried out the research to present a management plan for the port. In supply duct system, the opening size of the port had a tendency to increase and then decrease later when it gradually becomes closer toward the bulkhead at the beginning of the duct the minimum opening degree is to appeared as 56%. In the exhaust system, port size is the smallest at the beginning of duct as 15%, has shown a tendency to increase towards the bulk head. As results of estimating the air flow rate for 300 m intervals, the exhaust flow rate in the center of tunnel appeared to be extremely low as 8.1% and 12.5% when port size is constant and is adjusted supply type. Thus, even if the normal ventilation efficiency is declines, yet it is highly recommend adjusting the port size in order to obtain a uniform flow rate at fire accidents.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.5
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• pp.683-690
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• 2021

The ventilation system of the engine room of a ship is generally installed to supply the combustion air necessary for the internal combustion engine and to remove the heat source generated in the engine room, and it must satisfy the international standard (ISO 8861) for the design conditions and calculation standards for the ventilation of the ship engine room. The response delay of the ventilation system including the fire detector is affected by the airflow formed inside the area and the location of the fire detector. In this study, to improve the initial fire detection response speed of a fire detector installed on a fishing vessel and to maintain the sensitivity of the installed detector, the smoke behavior was simulated using the air flow field inside the engine room, the amount of combustion air in the internal combustion engine, and the internal pressure of the engine room as variables. Analysis of the simulation results showed that reducing the flow rate in the air flow field and increasing the vortex by reducing the internal pressure of the engine room and installing a smoke curtain would accelerate the rise of the ceiling of the smoke component and improve the smoke detector response speed and ventilation system.