Fire Science and Engineering (한국화재소방학회논문지)

Korean Institute of Fire Science and Engineering (한국화재소방학회)
권호 표지

A Characteristics of Smoke Layer Formation Affected Periodicity of Fire Plumes

Plume의 주기성이 연층형성에 미치는 영향

  • Published : 2002.06.01
Download PDF
⟨ Previous Next ⟩

Abstract

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.

ON-OFF 제트를 사용하여 plume의 주기성이 천장아래에 형성되는 연층에 미치는 정성적인 영향을 파악하였다. 사용된 연기는 가열에 의해 증발된 kerosene 입자를 섞은 질소가스이다. Laser sheet에 의해 산란된 유동장의 순간 상들은 디지털 비디오 카메라에 의해 녹화되었다. ON-OFF 제트와 연속제트의 연층형성 과정을 비교하므로서 화원근처에 형성되는 연층은 plume과 천장의 주기적인 충돌에 의해 지배됨을 확인하였다. 또한 plume의 주기적인 충돌은 연층을 두껍게하며, back-flow를 일으킴을 확인하였다.

Keywords

References

  1. Hamins A., Yang J. C., Kashiwagi T., 'An Experimental Investigation of the Pulsation Frequency of Flames', 24-th Combustion Symposium, 1695-1702(1992)
  2. Weckman E. J. and Sobiesiak A., 'The Oscillatory Behavior of Medium-scale Pool Fires', 22-th Combustion Symposium, 1299-1310(1988)
  3. Atkinson G., 'Smoke Movement Driven bt a Fire Under a Ceiling', Fire Safety Journal, Vol. 25, 261-275(1995) https://doi.org/10.1016/0379-7112(96)00003-3
  4. Walker J. D. A., Smith C. R., Cerra A. W. and Doligalski T. L., 'The impact of a vortex ring on a wall', J. Fluid Mech., Vol. 181, 99-140(1987) https://doi.org/10.1017/S0022112087002027
  5. Naitoh T., Banno O. and Yamada H., 'Longitudinal Vortex Structure in the Flow Field Produced by a Vortex Ring Impinging on a Flat Plate', Fluid Dynamics Research, Vol. 28, 61-74(2001) https://doi.org/10.1016/S0169-5983(00)00016-2
  6. McGrattan K. B. Forney G. P., Floyd J. E. and Hostikka S., Fire Dynamics Simulator(version 2.0) - User's Guide, NISTIR 6783(2001)(http://fire.nist.gov/fds)
  7. Kim M. B. and Han Y. S., 'Tracking of the Smoke Front Under a Ceiling by a Laser Sheet and Thermocouples', Fire Safety Journal, Vol. 34, 287-295(2000) https://doi.org/10.1016/S0379-7112(99)00048-X
  8. Alpert R. L., 'Turbulent Ceiling-Jet Induced by Large-Scale Fires', Combustion Science and Technology, Vol. 11, 197-213(1975) https://doi.org/10.1080/00102207508946699