• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.923-928
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• 2015

The FDS is one of the most used programs for fire analysis and needs an optimal grid selection for an accurate analysis. This study selected various grid aspect ratios (ARs) for selection of optimal grid and analyzed them with FDS v 6.1.2. A calculation time of 10 min. was used, which is enough to obtain the time average value of temperature changes. Temperature, visibility, and the time average value of mass balance are obtained from 200-600 s, which is a period of maintaining quasi-steady state. Two polyurethane fires of 1 [MW] and 2 [MW] in two enclosures of $10{\times}10{\times}3[m^3]$ and $20{\times}20{\times}3[m^3]$ were considered. Time variations of heat release rates, temperature, visibility, and mass balance were compared for ARs from 1-6. The heat release rates were accurate for all aspect ratios regardless of fire and enclosure sizes. The quasi-steady state temperature and visibility were well predicted for $AR{\leq}5$. Temperature drop and skewness of mass conservation, however, increased with increasing aspect ratio. Therefore, careful investigation of the grid size is recommended in performance-based design when $AR{\geq}3$, where temperature and visibility in early stage of a fire are important parameters. For accurate simulations of enclosure fires, grid sizes of 0.1~0.2 [m] and smaller in the vertical direction and $AR{\leq}2$ are recommended.

• Fire Science and Engineering
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• v.17 no.4
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• pp.98-104
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• 2003

Smoke control in il space 10 m${\times}$3 m floor and 5.4 m high around the stairway of a subway station platform was simulated by using FDS to investigate problems of smoke control in Daegue subway stations. Distributions of temperature and smoke particles, and variation of the number of particles with time for a 200 ㎾ polyurethane fire were compared. It was shown that the purge system fails to remove smoke efficiently and that the extraction system has the highest perfor-mance among the three smoke control systems for the given situations. Simply switching the purge system into extraction mode might improve much the smoke removal performance.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.1984-1989
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• 2008

In this study, fire simulations were performed to analyze the characteristics of the fire driven flow and the effects of the platform screen door on the smoke flow in the station, when the fire occurred in the center of the platform. Soongsil Univ. station (line number 7, 47m in depth underground) was chosen which was the one of the deepest underground subway stations in the Seoul metro, SMRT. The parallel computational method was employed to compute the heat and mass transfer eqn's with 6 CPUs of the linux clustering machine. The fire driven flow was simulated with using FDS code in which LES method was applied. The Heat release rate was 10MW and The Ultrafast model was applied for the growing model of the fire source. The 10,000,000 structured grids were used.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.811-818
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• 2018

A fire and explosion accident caused by a liquefied petroleum gas (LPG) welding and cutting torch gas leak occurred 10 m underground at the site of reinforcement work for bridge columns, killing four people and seriously injuring ten. We conducted a comprehensive investigation into the accident to identify the fundamental causes of the explosion by analyzing the structure of the construction site and the properties of propane, which was the main component of LPG welding and cutting work used at the site. The range between the lower and upper explosion limits of leaking LPG for welding and cutting work was examined using Le Chatelier's formula; the behavior of LPG concentration change, which included dispersion and concentration change, was analyzed using the fire dynamic simulator (FDS). We concluded that the primary cause of the accident was combustible LPG that leaked from a welding and cutting torch and formed a explosion range between the lower and upper limits. When the LPG contacted the flame of the welding and cutting torch, LPG explosion occurred. The LPG explosion power calculation was verified by the blast effect computation program developed by the Department of Defense Explosive Safety Board (DDESB). According to the fire simulation results, we concluded that the welding and cutting torch LPG leak caused the gas explosion. This study is useful for safety management to prevent accidents caused by LPG welding and cutting work at construction sites.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.3
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• pp.223-228
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• 2009

The aim of this research is to analyse the dynamic characteristics of the hot upper smoke layer in case of fire in a tunnel. In order to get the result, computer simulation technique has been used. The fire scenarios were set on the basis of standard cross section of national and express highways through NIST's FDS. As the area of a tunnel increased, the influence of the wind velocity decreased. Furthermore, the influence of the slope of a road was reduced as the wind velocity increased. On the other hand, as the wind velocity increased, the influence of the slope of a road decreased. This phenomena is believed to be caused by the cooling effect of wind which is over 1 m/s in speed, hence, reducing the influence of the effect of slope.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.11a
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• pp.143-146
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• 2011

2009년 11월 14일 발생한 부산 실내사격장 화재와 관련하여 조사내용을 토대로 화재 시뮬레이션용 전선유체역학 모델인 FDS를 이용하여 재현하였으며, 시뮬레이션 결과와 화재당시 녹화된 CCTV 영상을 비교하였다. 2층 발사실에서 시작된 화재는 급격히 연소가 진행되어 약 3초 후에 휴게실로 확산되며, 약 7초 후에는 계단 및 1층 홀을 지나 사람들이 통행하는 인도에까지 연기가 분출되는 것으로 나타났다. 시뮬레이션 결과는 2층 발사실과 휴게실에 녹화된 CCTV 영상 및 1층 홀 옆의 귀금속가게에 녹화된 CCTV 영상과 거의 일치하였다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.118-119
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• 2018

In this study, it analyses the problems of the Fire Compartment in Goyang Bus Terminal. Based on analysed data, it is confirmed the necessity of the Smoke Compartment installation for Protecting the Smoke Spread in Large-Scale Buildings using of FDS(Fire Dynamics Simulation). In addition it suggest that the necessity of Smoke Compartment application method and Development of Design Guideline.

• Fire Science and Engineering
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• v.31 no.4
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• pp.80-85
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• 2017

Recently, in Korea, construction of high-rise buildings has been rapidly increasing. Therefore, in order to minimize the loss of life and property in the event of a fire, "performance-based design" which requires performance equal to or better than current regulations is obligatorily required. However, in the field of fire and evacuation simulation, which occupies a large part in the performance-based design, detailed technical guidelines have not yet been established. Therefore, various designers are proceeding with the computer simulation modelling by referring to the design report book previously performed. Especially, in the case of the fire simulation, according to the judgment of a designer the scenario type is selected and the input values is set. Even if the building is used for the same purpose, it is true that the result can be different depending on how and who designed it. Therefore, in this paper, we have investigated the fire scenarios type and scenarios input values by randomly examining 7 preliminary reports of performance-based design in B metropolitan city. We also propose the improvement strategy for fire simulation and lay the groundwork for establishment of technical guidelines for fire simulation for performance-based design.

• Journal of the Korean Society of Safety
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• v.27 no.5
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• pp.35-41
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• 2012

The Numerical simulation was performed on the flow field around the two-dimensional rectangular bluff body in order to complement the previous experimental results of the bluff body stabilized flames [1]. For both fuel ejection configurations against an oxidizer stream, the flame stability was affected mainly by vortex structure and mixing field near bluff body. FDS(Fire Dynamic Simulator) based on the LES(Large Eddy Simulation) was employed to clarify the isothermal mixing characteristic and wake flow pattern around bluff body. The air used atmosphere and the fuel used methane. The result of counter flow configuration shows that the flow field depends on air velocity but the mixing field is influenced on the fuel velocity. At low fuel velocity the fuel mole fraction is below the flammable limit and hence the mixing is insufficient to react. Therefore, as the result, the flame formed at low fuel velocity is characterized by non-premixed flames. For the flow field of co-flow configuration, flame stability was affected by fuel velocity as well as air velocity. the vortex generated by fuel stream has counter rotating direction against the air stream. Therefore, the momentum ratio between air and fuel stream was important to decide the flame blow out limit, which is result in the characteristic of the partially premixed reacting wake near extinction.

• Fire Science and Engineering
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• v.25 no.1
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• pp.34-41
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• 2011

This research examines problem that can happen in partial smoke control method among contiguity area smoke control system through engineering examination and CFD. And the ultimate purpose of this is to secure safety of a person inhabiting at fire department by presenting improvement plan. Now a days, in large space-area such as department store or mega-mall in which mainly applies "Partial Smoke Control Method", air is suppled from adjacent area and smoke is exhausted in fire room. For various reason, however, it is confirmed through simulation that if air is suppled in one direction, this can cause a fatal result to people of fire area because of the difficulty in securing the evacuation time. As an improvement plan, air is supplied at the same time in surroundings to fire department.