• 한국안전학회지
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• 제18권1호
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• pp.28-32
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• 2003

The present study investigates the spray characteristics of water mist nozzle with mid-low pressure for fire suppression. The examined nozzle types are swirl and spiral nozzle. The result shows that K factor of water mist nozzle is much smaller than those of general sprinkler. Spray angle of spiral nozzle is largest and more than $150^{\circ}$. SMD(Sauter Mean Diameter) of water mist nozzles is ranged between 100 and 200$\mu\textrm{m}$through measuring by image processing method. The spray pattern of spiral nozzle represent that water flux of first stream is 2 times larger than that of second stream. This study will contribute better understandings of the water-mist spray characteristics and useful daia for developing the water-mist nozzles.

• 한국기계가공학회지
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• 제10권3호
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• pp.60-66
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• 2011

In the present investigation, experimental studies were conducted on the fire suppression performance of twin-fluid water mist spray which is subjected to thermal radiation in a closed space. Downward-directed water-mist sprays, interacting with an under kerosene pool fire, were investigated in a test facility. The mass mean diameter of water-mist droplets were measured by PMAS under various flow conditions. The developed twin-fluid water mit spray nozzle satisfied the criteria of NFPA 750, Class 1. The mechanism of fire suppression by fine water mist was concluded to be the cooling of the fire surface which leads to the suppression of fuel evaporation. It was proved that the automatic twin-fluid water mist spray system under lower pressures could be applied to an industrial facilities.

• 설비공학논문집
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• 제15권7호
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• pp.572-578
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• 2003

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 attributed to the 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.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2008년도 춘계학술논문발표회 논문집
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• pp.200-203
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• 2008

Water mist fire suppression system utilizes the fire suppression features such as cooling of fire source, dilution of ambient oxygen, and shielding of radiation heat with the evaporation of microscopic water droplets. The momentum of water mist is relatively low and the infiltration of water mist to the fire source is not effective. In addition to lower penetration force, the evaporated water vapor is liable to decline to limited portion of fire source due to its light weight and sparse density. On the other hand, the cycling water mist system is expected to improve the penetration force of water mist as well as the dilution coverage capability with the stratified spray characteristics. At this paper we present the analyzed fire suppression capability of intermittent water spray pattern by use of FDS which is computational fire dynamics fire model. We expect this analysis shall be supportive to the development of the prototype of water mist nozzle.

• 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.

• 한국전산유체공학회지
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• 제11권4호
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• pp.56-61
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• 2006

Numerical simulation has been performed to investigate the characteristics of the mist flow through the fire suppression nozzles. The commercial CFD software, FLUENT with the proper modeling was applied for analyzing both the internal and external flow of the spray nozzles. Computations were made for the full cone nozzle in the operation range of the low pressure and high flow-rate. To validate the present computational procedure, numerical results are compared with measurements in terms of K-factor, SMD, axial spray velocity and spray angles. Numerical results suggested that the present numerical model can be used as an adequate tool for a design purpose of mist-spray nozzles.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 춘계학술대회 논문요약집
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• pp.106-106
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• 2004

보일러에서 연소된 후 배출된 가스는 탈황목적으로 설치된 흡수탑 내에 유입되어 Slurry Spray Nozzle에서 분사된 Limestone Slurry에 의해 배기가스중의 SO$_2$를 흡수한 다음 반응조로 떨어지게 되지만 분사된 액적의 일부는 배기가스의 압력에 의하여 같은 유동 방향으로 미세한 Mist의 형태로 배기가스와 함께 흡수탑의 Outlet Duct를 통해 빠져나간다. 이 Mist(액적크기 40 $\mu\textrm{m}$이하)에는 고형 성분이 함유되어 있는데 보통 Chloride농도가 높아 탈황설비 후단 (duct, GGH, Stack)에 plugging, 부식 등의 문제를 유발하므로 Spray Header상부에서 Mist Eliminator를 설치하여 Mist를 제거하도록 한다.(중략)

• 한국분무공학회지
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• 제22권4호
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• pp.175-184
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• 2017

The numerical investigation on the effects of water-mist characteristics has been carried out for the fire suppression mechanism. The FDS are used to simulate the interaction of fire plume and water mists, and program describes the fire-driven flows using LES turbulence model, the mixture fraction combustion model, the finite volume method of radiation transport for a non-scattering gray gas, and conjugate heat transfer between wall and gas flow. The numerical model is consisted of a rectangular enclosure of $L{\times}W{\times}H=1.5{\times}1.5{\times}2.0m^3$ and a water mist nozzle that be installed 1.8 m from fire pool. In the present study, the parameters of nozzle for simulation are the droplet size and the spray velocity. The droplet size influences to fire flume on fire suppression more than the spray velocity because of the effect of the terminal velocity. The optimal condition for fire suppression is that the droplet size and the spray velocity are $100{\mu}m$ and 20 m/s respectively.

• 한국화재소방학회논문지
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• 제34권4호
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• pp.7-12
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• 2020

본 연구에서는 미세물분무의 특성이 열복사 감쇠에 미치는 영향을 살펴보기 위한 수치해석 연구를 수행하였다. 고온의 복사 패널로부터 전파되는 열복사가 미세물분무를 통과하여 약화되는 과정을 FDS를 이용하여 해석하였고, 미세물분무의 분사유량, 액적평균입경과 분무각에 따른 영향을 분석하였다. 해석 결과로부터 분사유량의 증가와 액적크기의 감소가 열복사 감쇠 효과를 증가시키는 것을 알 수 있었다. 복사열이 통과하는 분무 공간 분포의 영향을 살펴보기 위해 분사각을 변화시켜 열복사 특성을 분석하였으며 분사각이 클수록 복사 감쇠 효과가 커지는 것을 확인하였다. 이것은 유사한 액적크기분포와 유량조건에서도 액적들이 공간적으로 더 넓게 퍼져 있는 경우 복사의 감쇠 효과가 더 커질 수 있음을 보여준다.

• 한국화재소방학회논문지
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• 제22권3호
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• pp.216-220
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• 2008

물분무소화설비는 화원의 냉각, 주변공기의 희석, 미세한 물방울의 증발에 의한 열차단과 같은 소화특성을 이용한다. 미분무수의 운동량은 입자가 큰 물방울에 비해 상대적으로 낮으며 화원의 침투능력도 효과적이지 못하다. 증발된 수증기에 의한 기여는 무게가 가볍고 밀도가 희박하여 화원에 일부분으로 제한되는 경향이 있다. 반면, 사이클식 미분무 패턴은 성층화된 분무 특성에 의해 공기 추출능력과 침투력이 개선될 것으로 예상된다. 이 논문에서는 유체공학적 화재모델인 FDS를 사용하여 교번식 미분무 패턴에 대해 분석된 소화능력을 다룬다. 저자는 이 분석이 미분무 노즐의 표본을 개발하기 위한 기본 개념을 제공할 수 있기를 기대한다.