• Steel and Composite Structures
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• 제10권2호
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• pp.129-149
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• 2010

The objective of this study is to formulate a general 3D material-structural analysis framework for the thermomechanical behavior of steel-concrete structures in a fire environment. The proposed analysis framework consists of three sequential modeling parts: fire dynamics simulation, heat transfer analysis, and a thermomechanical stress analysis of the structure. The first modeling part consists of applying the NIST (National Institute of Standards and Technology) Fire Dynamics Simulator (FDS) where coupled CFD (Computational Fluid Dynamics) with thermodynamics are combined to realistically model the fire progression within the steel-concrete structure. The goal is to generate the spatial-temporal (ST) solution variables (temperature, heat flux) on the surfaces of the structure. The FDS-ST solutions are generated in a discrete form. Continuous FDS-ST approximations are then developed to represent the temperature or heat-flux at any given time or point within the structure. An extensive numerical study is carried out to examine the best ST approximation functions that strike a balance between accuracy and simplicity. The second modeling part consists of a finite-element (FE) transient heat analysis of the structure using the continuous FDS-ST surface variables as prescribed thermal boundary conditions. The third modeling part is a thermomechanical FE structural analysis using both nonlinear material and geometry. The temperature history from the second modeling part is used at all nodal points. The ABAQUS (2003) FE code is used with external user subroutines for the second and third simulation parts in order to describe the specific heat temperature nonlinear dependency that drastically affects the transient thermal solution especially for concrete materials. User subroutines are also developed to apply the continuous FDS-ST surface nodal boundary conditions in the transient heat FE analysis. The proposed modeling framework is applied to predict the temperature and deflection of the well-documented third Cardington fire test.

• Journal of Advanced Marine Engineering and Technology
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• 제32권3호
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• pp.446-454
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• 2008

Control devices for fire safety systems located in a engine room are to be arranged at a safe position which is easily accessible during a fire. To develop an interpretation for the safe position in engine rooms, calculation and experiments are carried out to determine a correlation between radiant heat and distance from fire in this paper. On the basis of results of this research, the control devices for a main engine are to be installed in the behind side of an obstruction to reduce radiant heat from the fire of the main engine. In case of other control devices, they are also to be provided in the same manner of control devices for the main engine or are to be placed with 5 meters far from fire hazards.

• 한국안전학회지
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• 제26권2호
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• pp.20-25
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• 2011

The fire event occurred in fire proof zone often causes serious electrical problems such as shorts, ground faults, or open circuits in nuclear power plants. These would be directed to the loss of safe shutdown capabilities performed by safety related systems and equipments. The fire event can treat the basic design principle that safety systems should keep their functions with redundancy and independency. In case of a multi-core cable fire, operators can not perform their mission properly and can misjudge the situation because of spurious operation, wrong indication or instrument. These would deteriorate the plant capabilities of safety shutdown and make disastrous conditions. In this paper, the characteristic of cable fire is investigated and the heat-flux evaluation for cable fire is studied. Moreover, a diagnostic methodology for degraded cable in nuclear power plants is presented.

• 동력기계공학회지
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• 제18권2호
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• pp.19-24
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• 2014

This research conducts CAE analysis of fire damper and design of damper controlling system. The prediction of the design heat transfer was done the answer of fire damper could be obtained by using continuity equation of damper controlling and orthogonal array. Through the design analysis of optimal offshore construction, new fire damper of H-120 class was designed. Accordingly, this equipment will be tested in actual offshore construction. Finally, we could obtain fire damper of optimal design with orthogonal array. With the CAE results of this research, The offshore plant will obtain eco-friendly fire damper with a method to select optimal condition of fire damper with orthogonal array.

• 설비공학논문집
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• 제18권4호
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• pp.344-350
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• 2006

The present study investigates the characteristics of fire-driven heat flows and gas concentration in a compartment fire by using the modified VHS model (MVHS). The main idea of this model is to add some source terms for combustion products and oxygen consumption to the original VHS model for providing more accurate and useful information on gas concentration distributions as well as thermal fields. It is found that the present MVHS model shows fairly good agreement with the experimental data and the eddy breakup combustion model. The tilting angle of fire plume calculated by MVHS is larger than that of EBU model because the fire source of VHS is affected by ventilating flow less than EBU. However, this discrepancy is apparently reduced in the downstream region of fire source.

• 한국화재소방학회논문지
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• 제17권1호
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• pp.76-84
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• 2003

본 연구는 산업현장에서 단열재로 .사용되고 있는 폴리스티렌 폼, 폴리우레탄 폼, 폴리에틸렌 폼과 같은 플라스틱 단열재의 화재특성을 구명하고자 하였다. 플라스틱 단열재의 화재특성은 ISO 5660에 따라 콘칼로리미터 시험을 수행하였다. 사용된 실험재료는 국내에서 생산되는 상업용 플라스틱 단열재를 사용하였고 그들의 조성은 제조자에 의해 밝혀지지 않았다. 연구 결과플라스틱 단열재의 열방출율은 재료의 밀도와 열플럭스의 증가에 따라 증가하였다. 플라스틱 단열재 중 폴리에틸렌 폼이 최대열방출율 및 평균열방출율이 가장 크게 나타났고, 열플럭스 및 밀도의 증가에 따른 최대열방출율의 증가율도 가장 큰 것으로 나타났다. 플라스틱 단열재에 의한 화재예방을 위해 제품의 종류 및 열플럭스의 크기에 따른 열방출 평가 기준을 제시하였다.

• 한국안전학회지
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• 제31권2호
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• pp.18-25
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• 2016

The incandescent lamp is an electric light fixture with a tungsten filament heated to a high temperature, by passing an electric current through it, until it glows with visible light. The hot filament is protected from oxidation with a glass bulb that is filled with inert gas. The incandescent lamp has fire risk when combustible materials are close to its glass bulb. Because its lamp has the property which converts 90~95 percents of the electric power to heat energy. 2015 national fire statistics show that fires caused by lighting fixtures were 652 cases, and incandescent lamps(44 cases) and halogen lamps(53 cases) accounted for 15 percents in those of high heating light fixtures. Since incandescent lamp fires account for about 45 percents in the high heating light fixture, we could not overlook the fire risks by the incandescent lamp. Although many studies related with those have been conducted, incandescent lamp fires are continuously occurred. This study was carried out to study the fire risk of ignition of wood due to radiant heat of incandescent lamp. Radiant heat flux of the incandescent lamp was predicted by applying point source model, and critical distance for ignition of wood was calculated by applying integral model. The results from this study could applied to fire prevention activities related to light bulb, and it could be used in fire cause investigations related to radiant heat of incandescent lamp.

• 방재기술
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• 통권24호
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• pp.32-39
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• 1998

A room-corner fire scenario of ISO 9705 with flame spread model developed by Quintiere is applied to the interior finish materials to show the sensitivity of properties derived from AST, E-1321 and ASTM E-1354 is investigated and various range of thermal properties by the author were analyzed in the model. There are including flame heat flux and thermal inertia, lateral flame spread parameter, heat of combustion and effective heat of gasfication. The time for total energy release rate to reach 1MW is examined. Though some areas are neede for improvements, The model appears to predict good results with all the range of input properties and could be

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1798-1803
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• 2003

In this work the dynamic heat transfer occurring in a cable penetration fire stop system built in the firewall of nuclear power plants is three-dimensionally investigated to develop a test-simulator that can be used to verify effectiveness of the sealants. The dynamic heat transfer can be described by a partial differential equation (PDE) and its initial and boundary conditions. For the shake of simplicity PDE is divided into two parts; one corresponding to the heat transfer in the axial direction and the other corresponding to the heat transfer on the vertical layers. Two numerical methods, SOR (Sequential Over-Relaxation) and FEM (Finite Element Method), are implemented to solve these equations respectively. The axial line is discretized, and SOR is applied. Similarly, all the layers are separated into finite elements, where the time and spatial functions are assumed to be of orthogonal collocation state at each element. The heat fluxes on the layers are calculated by FEM. It is shown that the penetration cable influences the temperature distribution of the fire stop system very significantly. The simulation results are shown in the three-dimensional graphics for the understanding of the transient temperature distribution in the fire stop system.

• 대한중풍순환신경학회지
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• 제12권1호
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• pp.24-31
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• 2011

Objective : Fire and heat related symptoms and signs are considered common in acute stage of diseases. The purpose of this study is to evaluate the occurrences and changes of fire and heat related symptoms and signs in acute cerebral infarction patients. Method & subjects : 40 acute cerebral infarction patients hospitalized in Oriental medicine hospital, Kyung-Hee University, who had examined and diagnosed 2 or 3 times based on oriental medical diagnosis were selected. We chose 23 as fire and heat related symptoms and signs from 94 diagnostic articles, and we added all those scores together of each patient. We analysed the scores of fire and heat related symptoms and signs as the time passed, and depending on oriental medical diagnosis. Result : In acute cerebral infarction patients of this study, 4 of fire and heat related symptoms and signs were took 1st, 2nd, 4th and 8th places in most changeable 10 articles of total 94 articles. The mean score of fire and heat related symptoms and signs of all patients were decreased significantly over the 3 times of measurements. The 8 patients diagnosed as fire and heat diagnosis at visit1 were samely diagnosed as fire and heat diagnosis at visit2, and at visit3 5 patients of them except for 3 patients excluded between visit2 and visit3, were still diagnosed as fire and heat diagnosis. At all of 3 measuring times, the scores of fire and heat related symptoms and signs of fire and heat diagnosis group were higher than non-fire and heat diagnosis group. Conclusion : This study indicated that fire and heat related symptoms and signs were very changeable phenomenon in acute cerebral infarction patients. And they decreased as time goes on.