• Title/Summary/Keyword: Smoke layer

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A Numerical Study on the Smoke Behavior by Solar Radiation through Ceiling Glass in Atrium Fires

  • Jeong, Jin-Yong
    • International Journal of Air-Conditioning and Refrigeration
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    • v.10 no.3
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    • pp.117-128
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    • 2002
  • This paper describes the smoke filling process of a fire field model based on a self-deve-loped 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-$\varepsilon$ turbulence model with buoyancy production term. Also it solves the radiation equation using the discrete ordinates method. Compressibility is assumed and the perfect gas law is used. Comparison of the calculated upper-layer average tempera-ture and smoke layer clear height with the zone models has shown reasonable agreement. The zone models used are the CFAST and the NBTC one-room. For atrium fires with ceiling glass the ceiling heat flux by solar heat causes a high smoke temperature near the ceiling. However, it has no effect on the smoke movement such as the smoke layer clear heights that are important in fire safety. In conclusion, the smoke layer clear heights that are important in evacuation activity except the early of a fire were not as sensitive as the smoke layer tem-perature to the nature of ceiling heat flux condition. Thus, a fire sensor in atrium with ceiling glass has to consider these phenomena.

Experiments on Smoke Filling in a Large Space (대공간 축연실험)

  • Han, Yong-Sik;Kim, Myeong-Bae;Jang, Yong-Jae;Yun, Myeong-O;Kim, Jin-Gon
    • 한국연소학회:학술대회논문집
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    • 1998.10a
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    • pp.37-46
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    • 1998
  • In this experiments, smoke filling behaviors in a large space were investigated. Also, it found that the smoke filling time can be predicted with a simplified zone model. Thermocouples were used to measure the temperature of the hot gases layer and also later to determine the smoke layer depth. Height markers were also hung from the roof so that observers could visibly assess the smoke layer depth.

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An experimental study of convective smoke filling (유동에 의한 연층 확산에 관한 실험적 연구)

  • 김명배;한용식
    • Fire Science and Engineering
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    • v.11 no.3
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    • pp.3-14
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    • 1997
  • An experimental investigation of smoke spread in a corridor is made using thermocouples and visualization technique with a laser beam sheet. A speed of smoke front under a ceiling is measured by thermocouple trees. Visualization of the ceiling jet formation and of smoke filling process is carried out to observe lowering of the smoke layer. From the results, a large-scale convective motion the corridor plays dominant roles for smoke spread from visualized photos together with temperature records. A circulating motion of fluid transports some smokes to some regions where its momentum is effective. It is therefore showed that the conventional concept of lowering smoke with two-layer zone model has some restrictions for the corridor because the lowering of smoke layer has been thought to be mass transport due to relatively small scale motion such as decrease of buoyancy, mass diffusion and momentum exchange.

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An Experimental and Analytical Studies on the Smoke Movement by Fire (화재시 연기거동에 관한 실험 및 해석적 연구)

  • Shin, Yi-Chul;Kim, Soo-Young;Lee, Ju-Hee;Kwon, Young-Jin
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 2008.04a
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    • pp.15-18
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    • 2008
  • A study on the fire and smoke behavior on experiments and analysis through STAR-CD in using about behavior analysis of the smoke. Kerosene of 3L in using on the experimental garden of 30cm in diameter same applies to heat release rate(HRR), buoyant force by Plume can be calculated at a rate of 1m/s. The result of experiment in average of velocity were 0.29m/s, and interpreted result were 0.28m/s. Besides, it is proved by interpreted that behavior of smoke movement can be not observed in the experiment. After smoke is Plume increased, ceiling-jet in formation being descend in smoke layer will be more thick smoke layer, and then vertical wall is collapsed in formation of wall-jet being descend. It is defined that smoke layer is more thick through descending course in wall-jet and ceiling-jet.

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SMOKE SPREAD IN A CORRIDOR

  • Kim, Myung-Bae;Han, Yong-Shik;Park, Jun-Seok
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 1997.11a
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    • pp.464-471
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    • 1997
  • Convective smoke spread in a corridor is experimentally investigated using thermocouples and visualization technique with a laser beam sheet. The speed of smoke front under a ceiling is measured by a series of thermocouples. Visualization of the ceiling jet formation and of smoke filling process is carried out to observe the lowering of a smoke layer. From the results, a large-scale convective motion plays dominant roles for smoke spread in the vicinity of the end of the corridor from visualized photos along with temperature records. The large-scale convective motion of the smoke is generated from the impingement of the ceiling jet front on the end of the corridor, and thus turning the flows toward the floor. Such a circulating motion of fluid transports some smoke to some region where its momentum is effective. It is therefore shown that the conventional concept of lowering smoke in the two-layer zone model has some restrictions for the corridor because the lowering of smoke layer has been thought to be mass transport due to relatively small scale motions such as the decrease of buoyancy, mass diffusion and momentum exchanges.

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An Experimental and Analytical Studies on the Smoke Movement by Fire in High Rise Building (초고층 건축물의 화재 시 피난로 연기거동에 관한 실험 및 해석적 연구)

  • Shin, Yi-Chul;Kim, Soo-Young;Lee, Ju-Hee;Kwon, Young-Jin
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2008.05a
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    • pp.11-14
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    • 2008
  • A study on the fire and smoke behavior on experiments and analysis through STAR-CD in using about behavior analysis of the smoke. Kerosene of 3L in using on the experimental garden of 30cm in diameter same applies to heat release rate(HRR), buoyant force by Plume can be calculated at a rate of 1m/s. The result of experiment in average of velocity were 0.29m/s, and interpreted result were 0.28m/s. Besides, it is proved by interpreted that behavior of smoke movement can be not observed in the experiment. After smoke is Plume increased, ceiling-jet in formation being descend in smoke layer will be more thick smoke layer, and then vertical wall is collapsed in formation of wall-jet being descend. It is defined that smoke layer is more thick through descending course in wall-jet and ceiling-jet.

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A Study on Smoke Filling in a Large Space (대공간에서의 연기축적에 관한 연구)

  • 김진곤;윤명오;한용식;김명배;김충익;유홍선;김상욱
    • 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.

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A Characteristics of Smoke Layer Formation Affected Periodicity of Fire Plumes (Plume의 주기성이 연층형성에 미치는 영향)

  • 한용식;김명배;오광철;신현동
    • Fire Science and Engineering
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    • v.16 no.2
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    • pp.38-42
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    • 2002
  • This experiment is to understand a characteristics of smoke layer formation affected periodicity of fire plumes. The ON-OFF jet was used to constitute the oscillating flow, which was formed by a mixture of nitrogen gas with kerosene particles. The instantaneous images was obtained by digital video camera using laser sheet technique. The results were confirmed that the smoke layer in the near fire source comprise vortices which are formed by impingement from the periodicity of fire plume. The periodic impinging of plumes were thickened the smoke layer and produced the back-flow.

A Numerical Study of Smoke Movement in Atrium Fires with Ceiling Hea Flux (천장에 열 유속을 갖는 대형 공간에서 화재 발생시 연기거동에 대한 수치해석적 연구)

  • 정진용;유홍선;김성찬;김충익
    • 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.

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How Visual-Field Obstruction from Fire Smoke Influences a Resident's Necessary Time to Reach Fire Escape and Evacuation Route in a High-rise Apartment Housing (연기발생으로 인한 시야장애가 초고층 공동주택 거주자의 피난계단실 진입시간과 피난경로에 미치는 영향)

  • Seo, Sang-Mok;Choi, Jun-Ho;Hong, Won-Hwa
    • Journal of the Korean housing association
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    • v.19 no.5
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    • pp.103-110
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    • 2008
  • The purpose of this study is to know how visual-field obstruction from fire smoke influences a resident's necessary time to reach fire escape and evacuation movement in a high-rise apartment housing. Generally, fire smoke not only gives visual-field obstruction and breath troubles to residents but interrupts their evacuation behavior. If a fire smoke layer is formed in the core department when evacuee enters at the evacuation staircase until, residents will be made to undergo a range of vision obstacle. In order to set a situation like that, participants wore eye bandage which had been made especially before the experiment. Also as a comparative standard, through no.1442 Japanese construction ministry notices about the building evacuation safety verification method, this study calculated smoke layer's dissent time and evacuation time. Then to compare with the former, the participants without an eye bandage joined a experiment once again. This study has understood how fire smoke effects on one's evacuation delay by analyzing residents' evacuation time to reach the staircase and movement route, however, in this study a toxic gas is not considered because it might threaten participants not to breathe.