• Title/Summary/Keyword: 열 복사

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Thermal Characteristics of Fire-Protection Foams Exposed to Radiant Heating (복사열에 노출된 소방용 폼 약제의 열적 특성 연구)

  • Kim, H.S.;Hwang, I.J.;Kim, Youn-J.
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1570-1575
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    • 2004
  • In order to evaluate the performance of fire-fighting agents used to protect structures from heat and fire damages, the thermal characteristics of fire-protection foams are experimentally investigated. The current research focuses on the destruction of a fire-fighting foam subjected to heat radiation. A simple repeatable test for fire-protection foams subjected to fire radiation is developed. This test involves foam generation equipment, a fire source for heat generation, repeatable test procedures, and data acquisition techniques. Results of the experimental procedure indicated that each thermocouple within the foam responded in a similar manner and gradually to a temperature of $15^{\circ}C{\sim}20^{\circ}C$. At this point, each trace generally rises to a temperature of approximately $90^{\circ}C$. The temperature gradient in the foam as time passes increases with increased foam expansion ratio. In addition, it is determined that the temperature gradient along the foam for depth decreases with increased foam expansion ratio.

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Protection Efficiency from Solar Radiation and Ultraviolet Radiation by Fabrics (소재에 따른 자외선.복사열 차단력)

  • 김경수;최정화
    • Journal of the Korean Home Economics Association
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    • v.40 no.10
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    • pp.77-85
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    • 2002
  • This study was conducted to evaluate the efficiency of various fabrics in protecting from solar radiation and ultraviolet radiation(UV). Six kinds of fabrics were selected and examined in singles or doubles. It was studied how the materials and the thickness of air layer between the fabric and the floor affected the protection efficiency of fabrics from sunlight. The results were as followes; 1) Protection from solar radiation: In the case of over 2 cm air layer, doubled fabric composed of aluminum coating-nylon and white or black polyester/cotton(T/C) was the most protective(p<0.001). In the case of 0 cm air layer, the case without fabric and white T/C were more effective(p<0.001). And the thicker the air layer the more effective the protection. 2) Protection from UV : Doubled fabric composed of aluminum coating-nylon and black T/C was the most protective(p<0.001) and the thinner the air layer the more effective the protection(p<0.001).

Analysis on the thermal development of radiatively participating pipe flow with nonaxisymmetric convective heat loss (비축대칭 대류열손실 경계조건하에서 원관내 복사에 관여하는 매질의 층류 열적 발달의 수치해석)

  • ;;Baek, Seung-Wook
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.11
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    • pp.2995-3002
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    • 1995
  • The cooling problem of the hot internal pipe flow has been investigated. Simultaneous conduction, convection, and radiation were considered with azimuthally varying convective heat loss at the pipe wall. A complex, nonlinear integro-differential radiative transfer equation was solved by the discrete ordinates method (or called S$_{N}$ method). The energy equation was solved by control volume based finite difference technique. A parametric study was performed by varying the conduction-to-radiation parameter, optical thickness, and scattering albedo. The results have shown that initially the radiatively active medium could be more efficiently cooled down compared with the cases otherwise. But even for the case with dominant radiation, as the medium temperature was lowered, the contribution of conduction became to exceed that of radiation.n.

Thermal analysis inside a small chamber including radiation (미소 챔버 내 복사열전달을 수반한 열유동 해석)

  • Lee, Hyung-Sik;Do, Gi-Jung;Lee, Sang-Ho
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.194-198
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    • 2006
  • In this study, numerical modeling was performed to analyze air flow including radiation heat transfer inside a small chamber. Characteristics of heat transfer between source plate and target through glass are investigated for various surface temperature of heat source plate with buoyancy effect due to gravity force. Conduction heat transfer through the glass is considered and heat source plate is assumed to be a black body. Target surface temperature is largely affected by the radiation heat transfer. It can also be seen that as the source temperature increases target surface is dominated by radiation rather than convective heat transfer by air.

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Analysis for Measuring the Thermal Diffusivity of Multilayered Composites in Flash Method (다층복합재료의 열확산계수를 섬광법으로 측정하기 위한 해석)

  • Lee, K. S.
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.7 no.4
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    • pp.477-482
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    • 1983
  • 섬광법의 응용범위를 증대하기 위하여 시편 저, 후면에서 복사와 대류 열손실이 있고, 전면에 임 의 열원이 가해지는 3층 복합재료의 열확산 방정식을 Green 함수를 도입하여 해석하였다. 본 해 석결과는 고체 재료를 1층 재료로 표면처리를 실시한 얇은 층 또는 코오팅 재료를 2층재료로, 용 기내에 들어있는 액체나 기체를 3층 재료로 하여 저온으로부터 고온에 이르기까지 광범위한 온 도에 걸쳐 열확산 계수를 구하는데 응용될 수 있다.

Con-heater를 이용한 인화성액체의 연소특성에 관한 연구

  • Park, Hyung-Ju;Kim, Hong;Jung, Ki-Chang;Lee, Jung-Yoon
    • Proceedings of the Korean Institute of Industrial Safety Conference
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    • 2003.10a
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    • pp.196-201
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    • 2003
  • 대부분의 고체와 액체의 연소는 고체의 열분해에 의해 생성되는 가연성 기체나 액체의 증발에 의한 가연성증기가 공기중에 확산되는 형태의 확산연소이다. 이런 확산 연소에서 연소속도를 지배하는 요소는 연료와 산화제의 확산속도이며 고체와 액체 연료의 경우 기체상태의 열분해 생성물이나 증기의 생성속도가 연소속도에 영향을 미치는 요소가 된다. 이러한 형태의 연소에서 연료와 산화제의 공급상태에 따라 발열량 및 화염의 형태 등이 영향을 받게 된다. 화재에서 화재의 확대에 영향을 미치는 요소들 중에 화염의 높이와 복사열 에너지 등이 있다.(중략)

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여름철 양돈장의 방서 대책

  • Heo, Mun-Do
    • The Korea Swine Journal
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    • v.10 no.6 s.106
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    • pp.89-94
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    • 1988
  • 신생자돈의 환경온도는 생시부터 7일까지 30-50$^{\circ}C$, 습도는 60-80%가 좋으며, 모돈은 12-23$^{\circ}C$ 범위이다. 한편, 방서대책의 원리로 돈사내의 기류를 촉진시켜 주고 복사열을 방지해야 한다

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