• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.128-132
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• 1997

The conventional fire detection devices are operated after a processed fire phase, which are sensing only a high density of smoke level or high temperature heat. They are not so precision to detect a fire in the early phase to protect the facility from the fire. We need to develope a new high precision smoke detection system to keep expensive industial facilities most reliably from fire. A new optical precision smoke detection system was developed. It monitors very low level density of smoke psrticles in the air. It is operated continuously through many years without a stop or any malfunction. The developed precision smoke detection system will be installed in important industrial facilities,such as power plants, underground common tunnel,main control rooms,computer rooms etc.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1998.11a
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• pp.53-60
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• 1998

In this study, smoke filling behaviors in a large space were investigated. For experimental study, thermocouples were used to measure the temperature of the hot gases layer and also to determine the smoke layer depth. Height markers were also hung from the roof so that observers could visibly assess the smoke layer depth. Ethanol was used as fuel. The smoke filling times were predicted with zone model and field model and numerical results were compared with experimental data. Good results were obtained.

• Fire Science and Engineering
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• v.12 no.3
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• pp.11-20
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• 1998

A new experimental technique using a laser sheet and thermocouples is introduced to evaluate an intuitive criterion for tracking of a smoke front using thermocouples. From synchronized photos of the smoke front along with temperature signals, the intuitive criterion is shown to be acceptable. Smoke visualization by a laser sheet proves to have several advantages over the conventional techniques such as the use of smoke generators.

• Journal of Mechanical Science and Technology
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• v.16 no.11
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• pp.1485-1496
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• 2002

In order to investigate the fire-induced smoke movement in a three-dimensional room with an open door, numerical and experimental study was performed. The center, wall, and corner fire plumes for various sized fires were studied experimentally in a rectangular pool fire using methanol as a fuel. The numerical results from a self-developed SMEP (Smoke Movement Estimating Program) field model were compared with experimental results obtained in this and from literature. Comparisons of SMEP and experimental results have shown reasonable agreement. As the fire strength became larger for the center fires, the air mass flow rate in the door, average hot layer temperature, flame angle and mean flame height were observed to increase but the doorway-neutral-planeheight and the steady-state time were observed to decrease. Also as the wall effect became larger in room fires, the hot layer temperature, mean flame height, doorway-neutral-planeheight and steady-state time were observed to increase. In the egress point of view considering the smoke filling time and the early spread of plume in the room space, the results of the center fire appeared to be more dangerous as compared with the wall and the corner fire. Thus it is necessary to consider the wall effect as an important factor in designing efficient fire protection systems.

• Tunnel and Underground Space
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• v.12 no.2
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• pp.92-98
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• 2002

In this study reduced-scale experiments were conducted to analyze smoke movement in tunnel fire with jet fan, The 1/20 scale experiments were carried out under the froude scaling using gasoline pool fire range from 6.6 to 12.5 cm in diameter with total heat release rate from 0.714 to 4.77 kW. In the case of fires under the 2.5kW, backlaying was reduced about 40cm and smoke was effectively controled in downstream of the fan when operating the fan. The smoke layer was moved down and the ceiling temperature was decreased compared to that of without fan case in upstream of the fan, but the temperature in the lower part of the tunnel was increased.

• Journal of the Korean Society of Mechanical Technology
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• v.20 no.6
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• pp.739-744
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• 2018

In this study, effects of reducing white smoke at a heat exchange system for white smoke reduction were studied in the winter season. For this purpose, the heat transfer processes on the exhaust air were investigated by Solidworks. Five wave heat exchangers of air-to-air and air-to-water type were applied for the exhaust air heat recovery. The analytical condition of the exhaust air was fixed and the computational analysis was performed according to the change of SA(supply air) inlet velocities. In order to evaluate the performance of the heat exchange system for white smoke reduction, W(water)/SA recovered capacities and the temperature/absolute humidity reduction rate were calculated. As SA inlet velocity increased, the exit temperature and absolute humidity of the mixing zone were reduced by up to about $40^{\circ}C$ and 0.12kg/kg respectively. Also, W/SA recovered capacities increased linearly up to about 35%.

• Fire Science and Engineering
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• v.13 no.4
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• pp.20-29
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• 1999

This paper describes the smoke filling process of a fire field model based on a self-developed SMEP(Smoke Movement Estimating Program) code to the simulation of fire induced flows in the two types of atrium space containing a ceiling heat flux. The SMEP using PISO algorithm solves conservation equations for mass, momentum, energy and species, together with those for the modified k- epsilon turbulence model with buoyancy term. Compressibility is assumed and the perfect gas law is used. The results of the calculated upper-layer average temperature and smoke layer interface height has shown reasonable agreement compared with the zone models. The zone models used are the CFAST developed at the Building and Fire Research Laboratory NIST U.S.A. and the NBTC one-room of FIRECALC developed at CSIRO, Australia. The smoke layer interface heights that are important in fire safety were not as sensitive as the smoke layer temperature to the nature of ceiling heat flux condition.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.7
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• pp.476-482
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• 2014

In this study, the characteristics of emulsified fuel and engine emissions were studied with engine dynamometer. Microexplosion took place in the combustion chamber. While combustion, emulsion fuel scattered to micro particles and it caused to smoke reduction. The heat produced from water vapour reduce the temperature of internal combustion chamber and it caused to inhibition of NOx production. It can be verified by the lower exhaust temperature of each ND-13 mode using emulsion fuel than that of MDO fuel. The NOx and smoke concentration were reduced by increasing water content in emulsion fuel. The power also decreased according to the increment of water content of emulsion fuel because emulsion fuel has low calorific value due to high water content than MDO. As a result of ND-13 mode test with 17% moisture content, it was achieved 24% reduction in NOx production, 76% reduction in smoke density, 11% reduction of $SO_2$ and 13% reduction in power loss.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.284-289
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• 2019

The Korea Foldable safe pathway system is an evacuation support system to get temporary evacuation route in railway tunnel and large space fires. A prevention smoke screen is unfolded in fires and it is needed to prevent heat and smoke from fire source. Therefore, ventilation system for positive pressure condition is equipped with foldable safe pathway system. Numerical analyses of temperature and pressure distribution with distance from fire source were performed considering fire scenario of new train vehicle. The smoke temperatures did not exceed $200^{\circ}C$ that distance from the fire source was more than 20 m and smoke pressure was reduced with distance from fire source. Maximum smoke pressure was 14 Pa and average pressure was 6 Pa in position of prevention smoke screen. As results, to install foldable safe pathway system, ventilation system is need to maintain 6 Pa positive pressure condition.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1996.11a
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• pp.5-9
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• 1996

In foreign country such as U.S.A and Japan, considerable research has been done regarding the spread of smoke in room of fire involvement by using computer. But, in our country it has not been. So, this paper presents a detailed qualitative description of phenomena which occures during typical fire scenarios through numerical analysis. This research, in the view of field model, is focused on finding out the smoke movement and temperature distribution. And it is planned to analyze governing equation including smoke diffusion equation by numerical analysis with finite volume method and non-staggered grid system. The SIMPLE method for pressure-velocity couple and power-law scheme for convection terms are used. It shows that a plume is formed, hot plume is formed, hot plume gases impinge on the ceiling and they spread across it. then, it eventually reaches the bounding walls of the enclosure. It takes 60s for smoke to fill the enclosure.