• Title/Summary/Keyword: Mist

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Water Mist Fire Suppression for Raised Subfloor Spaces

  • Kim, Woon-Hyung;Kim, James A. Milke
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 1997.11a
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    • pp.617-624
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    • 1997
  • Over 100 experiments have been conducted at the University of Maryland to evaluate the performance of a water mist fire suppression system for protection of an interstitial space below a raised subfloor. Experiments are conducted as part of an ongoing research effort to compare the fire suppression capabilities of various water mist system designs in a raised subfloor space. Water mist system design parameters considered in the investigation include means of actuation, concentration of water mist required for extinguishment of fires, and delivery mechanisms of water mist within close proximity to the fire. Delivery of the required concentration of water mist within close proximity to the fire is a principal factor governing the adequacy of water mist systems. Two sets of experiments have been conducted to document the performance of water mist system designs. One set is involved in documenting the concentration of water mist as a function of position within the space. The second set of experiments is concerned with the ability of water mist system designs to control fires in the space. One result of the research is the assessment of the ability of a water mist system to control fires at particular locations as a function of water mist density at that location.

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The Effects of Water Mist on the Compartment Fire

  • Ryou, Hong-Sun;Kim, Sung-Chan
    • International Journal of Air-Conditioning and Refrigeration
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    • v.12 no.1
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    • pp.30-36
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    • 2004
  • The present study investigates the fire suppression characteristics using a water mist fire suppression system. Numerical simulations of fire suppression with water mist are performed with considering the interaction of fire plume and water spray. The predicted temperature fields of smoke layer are compared with those of measured data. Numerical results agree with the experimental results within $10^{\circ}C$ in the case without water mist. In the case of fire suppression with water mist, numerical results do not predict well for temperature field in the gradual cooling region after water mist injection. But the predicted results of initial fire suppression are in good agreement with those of measured data. The reason for the discrepancy between predicted and measured data is due to the poor combustion modeling during the injection of water mist. More elaborate models for numerical simulation are required for better predictions of the fire suppression characteristics using water mist.

The Experimental Study on Mist Cooling Heat Transfer (초음파진동을 이용한 미세분무냉각 열전달에 관한 실험적 연구)

  • Kim, Yeung-Chan
    • Journal of ILASS-Korea
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    • v.15 no.4
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    • pp.202-207
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    • 2010
  • Mist cooling is widely employed as a cooling technique of high temperature surfaces, and it has heat transfer characteristics similar to boiling heat transfer which has the convection, nucleate and film boiling regions. In the present study, mist cooling heat transfer was experimentally investigated for the mist flow impacting on the heated surfaces of mico-fins. The mist flow was generated by supersonic vibration. Experiments were conducted under the test conditions of droplet flow rate, $Q=6.02{\times}10^{-9}{\sim}3.47{\times}10^{-8}\;m^3/s$ and liquid temperature, $T_f=30{\sim}35^{\circ}C$. From the experimental results, it is found that an increase in the droplet flow rate improves mist cooling heat transfer in the both case of smooth surface and surfaces of micro-fins. Micro-fins surfaces enhance the mist cooling heat transfer. Besides, the experimental results show that an increase in the droplet flow rate decrease the heat transfer efficiency of mist cooling.

A study on the Water Mist Fire Suppression Performance (미세 물 분무 소화 성능에 관한 연구)

  • 김봉환;김용판;문철진;홍철현;이형욱
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2002.05a
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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.

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A Study on the Fire Suppression Characteristics Using a Water Mist (물분무에 의한 화재제어 특성에 관한 연구)

  • 김성찬;유홍선
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.4
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    • pp.261-267
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    • 2003
  • The present study investigates the fire suppression characteristics using a water mist fire suppression system. Numerical simulations of fire suppression with water mist are performed with considering the interaction of fire plume and water droplet, droplet evaporation, and combustion of pool fire. The predicted temperature fields of smoke layer are compared with that of measured data. Numerical results agree with the experimental results within 5$^{\circ}C$ in the case without water mist In the case of fire suppression with water mist, numerical results dose not predict well lot temperature field in the gradual cooling region after water mist injection. But the predicted results of initial fire suppression are in good agreement with that of measured data. The reason of the discrepancy between predicted and measured data is due to the variation of turning rate during the injection of water mist. The effect of burning rate on the fire suppression is left as future study.

Analysis of Oil-Mist-Detector applied Capacitance Sensor (용량센서를 적용한 오일증기검출기 거동 해석)

  • Lee G.S.;Kim T.O.;Kim H.Y.;Ahn J.H.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.279-280
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    • 2006
  • This paper analysised Oil-Mist-Detector applied Capacitance Sensor which protects Diesel engine & human from explosion by detecting density of oil mist distribution. Assuming that distance between oil mists is same, Capacitance sensor plates & all oil mists could be analogized to capacitors. From equivalent circuit of Oil-Mist-Detector, variation of Capacitance which is related to Oil Mist's diameter & density of oil mist distribution is obtainable.

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A Study on the Performance of Water Mist Spray Fire Protection System (미세물분무 소화성능에 관한 연구)

  • 김봉환;김용판;문철진;홍철현;이형욱;최현호
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.7
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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.

Optimal Conditions for Mist Sensing and Removal in Automobile (자동차 내부의 김서림 감지 및 제거를 위한 최적의 조건)

  • You, Do-Hyun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.5
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    • pp.763-769
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    • 2012
  • For mist sensing, temperature-humidity sensor is attached on six positions of front glass and rearview mirror in automobile. Bottom-left side of front glass is the best position where mist is sensing. For mist removal, air conditioner is turned on intensity 1, 3 and is set the temperature at 17[$^{\circ}C$], 25[$^{\circ}C$]. And heater is turned on intensity 1, 3 and is set the temperature at 25[$^{\circ}C$], 32[$^{\circ}C$]. The best condition which mist is removed is temperature at 17[$^{\circ}C$] and intensity 3 of air conditioner mode. At this condition, total average value of humidity output voltage difference is 0.561[V]. Also, air conditioner mode is effective than heater mode for mist sensing and removal.

Determining Factors to Enhanced Oil Mist Filter Efficiency Using CFD Modeling (CFD모델링을 통한 오일 미스트필터효율 향상 결정요소에 관한 연구)

  • Shin, Hee-Jae
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.20 no.10
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    • pp.119-127
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    • 2021
  • Small drops in gas cause some problems for downstream equipments such as turbine, compressor and etc. In some cases, we are obliged to remove hazardous liquid mist from gas. In order to remove water or other liquids from the gas, there are some equipments like mesh mist eliminator and vane-plate mist eliminator. oil mist filter is a kind of liquid eliminator equipments used to remove the liquid with 1-10um droplet diameter from the gas. In this paper is determine the factors affecting the oil mist filter efficiency using CFD. length and angle of the filter were considered and the results and compare the results of the efficiency tests, showed error of less than 3%. optimum filter can remove more than 87.3% between 1 and 10um of oil mist.

Hair Changes with the Use of Mist during Hair Bleaching (탈색 시술 시 미스트 사용 여부에 따른 모발의 변화)

  • Kim, Eun Bi;Lim, Sun Nye
    • Textile Coloration and Finishing
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    • v.30 no.4
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    • pp.304-312
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    • 2018
  • This study reduced the number of hair bleachings and used a hair steamer machine to reduce hair damage during hair coloring. In addition, such treatment was given, focusing on the use of hair mist. When the $L^{\ast}a^{\ast}b^{\ast}$ values for bleached hair were measured using a spectrum colorimeter, the mist steamer-based hair revealed higher brightness. Hair damage was low when moisture contents were high after hair drying with the use of the mist steamer machine. The mist treatment-less hair showed more blurred cuticle boundaries than mist-treated hair. In other words, this confirms that cuticles are protected by the use of a mist steamer machine during hair bleaching. It appears that this could minimize hair loss and meet clients' aesthetic needs and satisfaction during color bleaching/coloring.