• Title/Summary/Keyword: Heat-Spread

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The Experimental Study for Radiant Heat Flux of Non-insulated Glazed Window in Fire (화재시 비차열 유리의 복사열에 관한 실험적 연구)

  • Park, Soo-Young;Seo, Hee-Won;Kim, Dae-Hoi;Wang, Nam-Woong;Yeo, In-Hwan;Choi, Dong-Ho
    • Fire Science and Engineering
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    • v.28 no.2
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    • pp.26-33
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    • 2014
  • Recently in Korea, the interest for using window and window-wall in building picks up due to the beauty and utilization of space. But, interior space of the buildings shall be compartmentalized by fire resistance structures in accordance with the Korean building codes to prevent the spread of flame and damage of human life in fire. In case of installing non-insulated glazed window in compartment wall, the flame spread to adjacent space and the damage of human life by radiant heat can occur in fire. On this study, to confirm the risk of radiant heat for non-insulated glazed window in fire, the fire resistance tests were conducted. The temperature rise and heat flux on unexposed space was measured and analyzed.

Study On Lagrangian Heat Source Tracking Method for Urban Thermal Environment Simulations (도시 열환경 시뮬레이션을 위한 라그랑지안 열원 역추적 기법의 연구)

  • Kim, Seogcheol;Lee, Joosung;Yun, Jeongim;Kang, Jonghwa;Kim, Wansoo
    • Journal of Korean Society for Atmospheric Environment
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    • v.33 no.6
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    • pp.583-592
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    • 2017
  • A method is proposed for locating the heat sources from temperature observations, and its applicability is investigated for urban thermal environment simulations. A Lagrangian particle dispersion model, which is originally built for simulating the pollutants spread in the air, is exploited to identify the heat sources by transporting the Lagrangian heat particles backwards in time. The urban wind fields are estimated using a diagnostic meteorological model incorporating the morphological model for the urban canopy. The proposed method is tested for the horizontally homogeneous urban boundary layer problems. The effects of the turbulence levels and the computational time on the simulation are investigated.

Study on development of Solar Collector using Oscillating Capillary Tube Heat Pipe (진동세관형 히트파이프를 이용한 태양열 집열기 개발에 관한 기초연구(I);작동유체의 내부 충진율과 경사각도의 영향)

  • Kim, Tae-Hoon;Kim, Jong-Soo;Ha, Soo-Jung;Im, Yong-Bin
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1394-1399
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    • 2004
  • Recently solar energy is representative in the technology development and spread of alternative energy. Specially in condition of solar collectors, they have had very various shape. This paper reports experimental study about the application of Oscillating Capillary Tube Heat Pipe to flat-plate solar collector. In conclusion, overall temperature distribution of OCHP was investigated by charging ratio and inclination angle. Respective charging ratio is 15%, 20%, 40% and respective inclination angle is horizontal, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, perpendicular. As a result of experiment, charging ratio 20% heat pipe has shown the most uniform temperature distribution and also performance of heat transfer has been the best.

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Estimating the Heat Island Development Using Landsat TM and AMeDAS Data

  • Harada, Ippei;M.A., Mohammed Aslam;Kondoh, Akihiko
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.450-452
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    • 2003
  • In the present investigation, an estimation of the growth of heat island development of Tokyo metropolis which accounts nearly 100 sq. km of areal spread has been carried out. Band 6 data of LANDSAT TM (Thematic Mapper) data acquired on August 1984 and 1994 have been used for estimating the expansion of the heat island development. Since the vegetation decrease is usually associated with the heat island development, a ratio of green covering has also been assessed using TM data. In order to establish the relationship with the air temperature, AMeDAS(Automated Meteorological Data Acquisition System) data have been correlated.

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An Experimental Study on the Application of Horizontal Barrier and In-Rack Sprinklers to Prevent Vertical Spread of Rack-type Warehouse Fires (랙크식 창고 화재의 수직 확산 방지를 위한 수평차단막과 In-Rack 스프링클러 적용에 관한 실험연구)

  • Park, Moon-Woo;Hong, Sung-Ho;Choi, Ki-Ok;Choi, Don-Mook;Kim, Soo-Jin
    • Journal of the Korean Society of Safety
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    • v.34 no.5
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    • pp.15-21
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    • 2019
  • A rack-type warehouse has the advantage of storing a large amount in a small area by loading goods vertically. But in terms of fire risk, the fire load is very high, which can cause massive damage in the event of a fire. In the United States, research has been actively conducted to minimize the spread of vertical fires, and relevant standards have been established and operated. In Korea, research and related standards are insufficient to prevent the vertical spread of rack-type warehouse fires. In this study, an experimental study was conducted to prevent the vertical spread of a rack-type warehouse fire using a horizontal barrier and in-rack sprinklers. As a result of the test, the horizontal barrier considering the continuous flame prevented the vertical spread of the flame for a certain time. However, the horizontal barrier with continuous flame did not show the effect of preventing continuous flame. The combination of the horizontal barrier and the in-rack sprinkler prevented the vertical spread of fire effectively. In addition, the heat collecting effect through the horizontal barrier was shown and helped the early operation of the in-rack sprinklers.

Assessment of Explicit Algebraic Stress/Heat-Flux Models for Reduction of Heat Transfer in a Vertical Pipe with Intense Heating (Explicit Algebraic Stress/Heat-Flux 모형을 이용한 벽면가열이 높은 수직관 내의 열전달 감소에 대한 수치적 해석)

  • Baek, Seong-Gu;Park, Seung-O
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.12
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    • pp.1724-1733
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    • 2003
  • This paper assesses the prediction performance of explicit algebraic stress and heat-flux models for reduction of heat transfer coefficient in a strongly-heated vertical tube. Two explicit algebraic stress models and four explicit algebraic heat-flux models are selected for assessment. Eight combinations of explicit algebraic stress and heat-flux models are used in predicting the turbulent gas flows with intense heating, which yields the significant property-variation. The results showed that the two combinations of GS-AKN and WJ-mAKN predicted the Nusselt number and the axial wall temperature variations well and that the predictions of Nusselt number with WJ-combinations spread in a wider range than those with Gs-combinations. WJ is the explicit algebraic stress model of Wallin and Johansson and GS is the model of Gatski and Speziale and that AKN is the explicit heat-flux model of Abe, Kondoh and Nagano and mAKN is the modified AKN.

A Study on the Modeling of Vertical Spread Fire of Exterior Panel by Fire Dynamic Simulation (FDS) (FDS를 이용한 외장재의 수직 확산 화재의 모델링에 관한 연구)

  • Min, Seh-Hong;Yoon, Jung-En
    • Journal of the Korea Safety Management & Science
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    • v.11 no.2
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    • pp.77-85
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    • 2009
  • Considering heat insulation and beautiful sight of construction, making use of exterior panels is increasing. Recently the exterior panels now are weak very much, and so in consequence of the weakness fire spreads rapidly. Compared with internal fire, external vertical fire spread rate goes rapidly and it is extensive in spread range, therefore it is dangerous very much. Accordingly, under present condition of poor standard of exterior panels, it is required to take measure to meet the appropriate situation. In this study, by making use of FDS(Fire Dynamic Simulation) program about external vertical fire of high rise building, fire behavior is searched by computer. It is important that realizing by computer fire modeling about external vertical fire must be included certainly in procedure of fire performance design in the future. In modeling program, FDS version 5 is available, and aluminium composite panel is applied in external panels. In this study, for realizing of actual fire condition, FDS is applied by details of fire scenarios considering influence of wind.

UPWARD FLAME SPREAD ON PRACTICAL WALL MATERIALS

  • Kim, Choong-Ik;Ellen G. Brehob;Anil K. Kulkarni
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 1997.11a
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    • pp.138-145
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    • 1997
  • Models of upward flame spread have been attempted in the past, but in the current work an emphasis has been placed on developing a practical model that will be useful across a broad range of materials. Some of the important aspects of the model we: the addition of external radiation to simulate a wall that is a part of an enclosure fire and has flaming walls radiating to it, the use of a correlation for flame heat feedback distribution to the sample surface based on data available in the literature, and the use of an experimentally measured mass loss rate for the sample material, In this paper, the development of the numerical model is presented along with predictions of flame spread for three materials: hardboard, a relatively homogeneous wood-based material; plywood, which is made of laminated wood bonded by adhesives; and a composite material made of fiberglass matrix embedded in epoxy. Predictions are compared with measured data at several levels of external radiation for each material. For the materials tested, the model correctly predicts trends and does a reasonable job predicting flame heights. The need for thermal property data for practical materials, which would be appropriate for flame spread models, is indicated by this work.

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Evaluation of Heat Loss by Means of Plasma Jet Ignition during Combustion Duration in the Constant Volume Vessel (정적연소실내에서의 플라즈마 제트 점화에 대한 연소기간중의 열손실산정)

  • 김문헌;문경태;박정서;김홍성
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.2
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    • pp.96-103
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    • 2003
  • In this paper, the heat loss to the constant volume vessel wall was investigated using instantaneous heat flux sensor, schlieren visualization, pressure rise curve. And the heat loss characteristics of plasma jet ignition were compared with conventional spark ignition. In case of plasma jet ignition, the flame kernel moves toward the center of combustion vessel in the initial period of combustion, and the flame surface spread out to the vessel wall. However, in case of conventional spark ignition, the flame surface contact with combustion vessel wall in the initial period of combustion. As a result, heat loss in the combustion duration for conventional spark ignition increase faster than that of plasma jet ignition. And the combustion enhancement rate of plasma jet ignition is higher than that of conventional spark ignition, and it was found that the heat loss rate is inversely proportional to the combustion enhancement rate.

An Experimental Study on Heat Transfer in a Falling Liquid Film with Surfactant (계면활성제의 농도가 유하액막의 열전달 특성에 미치는 영향에 관한 실험적 연구)

  • Kim, Kyung-Hee;Kang, Byung-Ha;Lee, Dae-Young
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.150-155
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    • 2006
  • Falling liquid plays a role in a wide variety of naturally occurring phenomena as well as in the operation of industrial process equipment where heat and mass transfer take place. In such cases, it is required that the falling film should spread widely on the surface forming thin liquid film to enlarge contact surface. An addition of surface active agent to a falling liquid film affects the flow characteristics of the falling film. In this study the heat transfer characteristics for a falling liquid film has been investigated by an addition of the surface active agents. The falling liquid film was formed on a vertical flat plate. As the mass flow rate of liquid falling film is increased, the wetted area is a little increased while the heat transfer rate as well as heat transfer coefficient is significantly increased. It is also found that both wetted area and heat transfer rate is substantially increased while heat transfer coefficient is a little increased with an increase in the surfactant concentration at a given mass flow rate.

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