• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.250-255
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• 2008

Most high-rise building and large building require a cooling tower. Closed cooling tower is a low noise and the high efficiency. also Closed cooling tower is available for four season. Performance of Closed cooling tower is judged by heat transfer coefficient. In this study, Heat transfer coefficient is compared with air velocity, spray flow, heat exchanger type.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1703-1708
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• 2003

The present study investigates the effect of injection angle of water mist on fire suppression characteristics by numerical simulation. In order to validate the temperature field by numerical simulation, the predicted results are compared with experimental data. It shows that the temperature difference between measurements and predictions are within $10^{\circ}C$ Numerical simulations of fire suppression are performed for 4 different injection angle($60^{\circ}$, $90^{\circ}$, $120^{\circ}$, and $180^{\circ}$). The grobal mean temperature over the fire compartment decrease with increasing of spray angle. The result shows that the heat transfer between droplets and gas phase are enhaced with the increasing of spray angle. Near the fire source, temperature field by the wide spray angle is slightly higher than that of narrow injection angle because of direct cooling of fire source.

• 한국안전학회지
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• 제18권2호
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• pp.28-33
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• 2003

The present study investigates the effect of injection angle of water mist on fire suppression characteristics by numerical simulation. In order to validate the temperature field by numerical simulation, the predicted results are compared with experimental data. It shows that the temperature difference between measurements and predictions are within $10^{\circ}C$. Numerical simulations of fire suppression are performed for 4 different injection angle($60^{\circ}$, $90^{\circ}$, $^120{\circ}$, and $180^{\circ}$). The global mean temperature over the fire compartment decrease with increasing of spray angle. The result shows that the heat transfer between droplets and gas phase are enhanced with the increasing of spray angle. Near the fire source, temperature field by the wide spray angle is slightly higher than that of narrow injection angle because of direct cooling of fire source.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2008년도 춘계학술논문발표회 논문집
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• pp.230-233
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• 2008

본 연구는 수분무 소화설비의 효용성에 대한 기초평가를 수행할 목적으로 FDS 수치시뮬레이션을 수행하였다. 화재강도 및 풍속의 변화에 따른 화재시 온도 및 연기농도에 대한 안전성 확보 효과를 분석하였다. 터널내 풍속이 없는 경우 수분무는 냉각효과에 의한 온도 및 연기농도 감소효과가 아주 우수하여 대피자의 안전성 확보에 효과적이었다.

• 대한기계학회논문집B
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• 제27권3호
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• pp.367-373
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• 2003

The present study investigates the fire suppression characteristics using a water mist fire suppression system. The fire extinguishing times are measured for various fire sources, fuel types, and different total flooding rates of water mist. Pool fire with hydrocabon fuel is successfully extinguished within a minute under the operating conditions of the water mist system. Two different regimes of the smoke layer cooling are observed, such as rapid and slow cooling processes. The regimes are divided by threshold time which is calculated with auto-correlation function. The threshold time for the initial cooling decreases with increasing water flow-rates and fire sources. These initial cooling effects play an important role in preventing the occurance of flashover fire by the initial fire suppression.

• 한국화재소방학회논문지
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• 제22권5호
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• pp.55-60
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• 2008

본 연구는 수분무 소화설비의 효용성에 대한 기초평가를 수행할 목적으로 FDS 수치시뮬레이션을 수행하였다. 화재강도(20MW, 50MW) 및 풍속의 변화에 따른 화재시 온도 및 연기농도에 대한 안전성 확보 효과를 분석하였다. 터널내 풍속이 없는 경우 수분무는 냉각효과에 의한 온도 및 연기농도 감소효과가 아주 우수하여 대피자의 안전성 확보에 효과적이었다. 화재강도가 커질수록 연기이동 억제효과는 감소한 결과를 나타났다. 또한 터널내 기류가 존재하는 경우에는 냉각효과에 의해서 연기의 성층화를 교란하며, 대피시 가시도를 저하시키는 것으로 나타났다. 따라서 수분무 소화설비는 화재발생시 대피자가 대피한 후에 이루어져야 할 것으로 판단된다.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2002년도 춘계학술대회논문집
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• pp.61-65
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• 2002

The present study was numerically and experimentally performed to investigate the fire suppression performance of water mist spray subjected to thermal radiation in closed space. Downward-directed water mist sprays to interact with an under kerosine pool fire were investigated in test facility. The mass mean diameters of water mist droplet were measured by PMAS under various flow conditions. The developed water mist spray nozzle was satisfied to the criteria of NFPA 750, Class 1. The mechanism of the fire suppression by water mist was concluded to be cooling of the fire surface which lead to suppressed of fuel evaporation. It was proved that the water mist spray system under lower pressures could be applied to underground fire protection system.

• 대한기계학회논문집B
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• 제34권2호
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• pp.203-212
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• 2010

수분류 스프레이 냉각은 많은 산업적인 응용분야에 넓게 사용되고 있다. 본 연구는 수분류 스프레이가 표면거칠기가 주어진 $900^{\circ}C$ 고온강판의 표면에 충돌하는 경우, 열유속 및 열전달계수의 정량적인 측정을 통해 표면거칠기가 수분류 스프레이 냉각에 미치는 영향을 고찰하였다. 이 때의 국소 열유속은 시편, 카트리지히터, 열전대의 조합으로 고안된 고유의 열유속게이지를 제작하여 엄밀하게 측정되었다. 평균 표면거칠기 높이를 기준으로 40, 60, $80{\mu}M$의 3 가지 표면과 매끈한 표면에 대한 수분류 스프레이 냉각 의 열전달 현상이 비교 및 평가되었다. 표면거칠기가 주어진 표면에서의 돌출물은 얇은 열 경계층두께를 통과할 수 있기 때문에 표면거칠기가 주어진 경우에 열전달은 뚜렷하게 증가하였고, 표면거칠기의 의한 열전달 향상 기구는 서로 다른 비등영역에 대해 구분하여 조사되었다.

• 한국분무공학회지
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• 제9권4호
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• pp.77-82
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• 2004

This paper describes the improvement of engine cooling system. To improve engine cooling performance, the authors approached in two ways. One is to increase water pump performance, changing of impeller shape and lightening of material were carried out. The second one is cooling efficiency rise, which were investigated with head gasket coolant flow passage optimization with flow visualization technique. The test results show that water pump performance was increased effectively, reduction of pump drive torque, and increase of pump flow-rate and pressure rise. Gasket hole pattern optimization test results represent an optimized head coolant flow which stands cross flow from exhaust to intake port side and small vortex were removed.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.597-602
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• 2008

The experiment of performance about closed-wet cooling tower(CWCT) was conducted in this study. The test section has the cooling water that flows from top part of a heat exchanger that has an entrance of cooling water with one and multi path. The heat exchanger consists of 15.88mm tubes with ten rows and ten columns and staggered arrangement. In this experiment, heat and mass transfer coefficients and range are calculated with variations of cooling water and path. The results indicated that operating CWCT using two path have the high values of heat and mass transfer coefficients and range than one path.