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Modeling and Numerical Simulation on Ignition and Transition to Flame Spread under a Microgravity Environment

Research Project

Project/Area Number 07650255
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Thermal engineering
Research InstitutionKYOTO UNIVERSITY

Principal Investigator

NAKABE Kazuyoshi  Dept.of Mechanical Engng., Kyoto University Assoc.Professor, 工学研究科, 助教授 (80164268)

Co-Investigator(Kenkyū-buntansha) INAOKA Kyoji  Dept.of Mechanical Engng., Kyoto University Instructor, 工学研究科, 助手 (60243052)
SUZUKI Kenjiro  Dept.of Mechanical Engng., Kyoto University Professor, 工学研究科, 教授 (00026064)
Project Period (FY) 1995 – 1996
Project Status Completed (Fiscal Year 1996)
Budget Amount *help
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1996: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1995: ¥1,700,000 (Direct Cost: ¥1,700,000)
KeywordsMicrogravity / Ignition / Flame propagation / Numerical Simulation / Equations of reaction rate / 火炎伝ぱ
Research Abstract

A theoretical model describing ignition and transition to flame spread over an inflammable solid material in a microgravity environment with and/or without a slow ventilation wind is developed for application to fire safety in a spacecraft. This study treats a thermally thin cellulosic paper accompanied with both solid and gas phase reactions. A process of ignition and subsequent flame spread on the solid material is complicated by strong coupling between chemical reactions and transport processes not only in the gas phase but also in the solid phase. The objectives of this study are to be able to obtain a more definitive understanding of the ignition and flame propagation mechanisms under a microgravity environment, and also to develop fire safety applications in a spacecraft. In fire safety applications, the transition from ignition to flame spread is crucial to determine whether a fire will be limited to a localized, temporary burn or will transit into a growth mode with a potential … More to become a large fire.
Axisymmetric heat and mass transport processes near the heated solid surface accompanied with solid and gaseous reactions were numerically calculated in a quiescent microgravity environment. 3-dimensional unsteady numerical computation was also performed in order to investigate the effects of the ambient wind and oxygen concentration on phenomena of ignition and subsequent flame spread over the surface, since even a slow ambient flow along the sample surface similar to a ventilation flow in a spacecraft has significant effects on flame propagation velocity, and might affect the mechanisms of smoldering and also gaseous combustion. A one-step global gas phase oxidation reaction and three global degradation reactions for the solid phase are used in the present model. The equations for temperature and concentrations are solved using an operator-splitting technique to prevent the solutions from diverging.
A higher oxygen concentration increases the gaseous temperature due to an increase in gas phase reaction rate and thus increases the energy feedback rate to the sample material, which increases the supply rate of combustible gaseous degradation products. The transition from autoignition to the flame spread is controlled by the energy feedback rate. Shortly after the ignition, the flame has an umbrella-like shape. The center portion of the flame becomes weaker with time and eventually disappears. Then, a ring-shape flame propagates radially outward. The flame near the propagation front is considered to be a premixed flame followed by a diffusion flame at its tail. Less

Report

(3 results)
  • 1996 Annual Research Report   Final Research Report Summary
  • 1995 Annual Research Report
  • Research Products

    (10 results)

All Other

All Publications (10 results)

  • [Publications] Kazuyoshi NAKABE: "Ignition and Transitoin to Flame Spread over a Thermally Thin Cellulosic Sheet in a Microgravity Environment" Combustion and Flame. 98. 361-374 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] Kazuyoshi NAKABE: "Group Combustion Behavior of Liquid Fuel Sprays under the Influence of Coherent Large Eddies" Proc.ASME/JSME Thermal Engng.(Eds.J.S.Fletcher & T.Aihara). 3. 149-156 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] 中部主敬: "円柱後流における燃料噴霧の群燃焼挙動" 日本機会学会論文集(B編). 61. 317-324 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] Kazuyoshi Nakabe・他5名: "Ignition and Transition to Flame Spread over a Thermally thin Cellubosic Sheet in a Microgravity Environment" Combustion and Flame. 98. 361-374 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] Kazuyoshi Nakabe・他4名: "Group Combustion Behavior of Liquid Fuel Sprays Under the Influence of Coherent Large Eddies" Proc.ASME/JSME Thermal Engineering (Eds.J.S.Fletcher & T.Aihara). 3. 149-156 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] Kazuyoshi Nakabe, et al.: "Ignition and Transition to Flame Spread over a Thermally Thin Cellulosic Sheet in a Microgravity Environment" Combustion and Flame. 98. 361-374 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] Kazuyoshi Nakabe, et al.: "Group Combustion Behavior of Liquid Fuel Sprays under the Influence of Coherent Large Eddies" Proc.ASME/JSME Thermal Engineering Conference (Eds.J.S.Fletcher & T.Aihara). 149-156 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] 中部主敬: "円柱後流における燃料噴霧の群燃焼挙動" 日本機械学会論文集(B編). 61・581. 317-324 (1995)

    • Related Report
      1996 Annual Research Report
  • [Publications] Kazuyoshi Nakabe: "Ignition and Transition to Flame Spread over a Thermally Thin Cellulosic Sheet in a Microgravity Environment" Combustion and Flame. 98. 361-374 (1994)

    • Related Report
      1995 Annual Research Report
  • [Publications] Kazuyoshi Nakabe: "Group Combustion Behavior of Liquid Fuel Sprays under the Influence of Coherent Large Eddies" Proc. ASME1JSME Thermal Engng. (Eds. J. S. Fletcher & T. Aiham). 3. 149-156 (1995)

    • Related Report
      1995 Annual Research Report

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Published: 1995-04-01   Modified: 2016-04-21  

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