Fire Science and Engineering (한국화재소방학회논문지)

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

Effects of Ventilation Condition on the Fire Characteristics in Compartment Fires (Part I: Performance Estimation of FDS)

구획화재에서 환기조건의 변화가 화재특성에 미치는 영향(Part I: FDS의 성능평가)

  • 황철홍 (대전대학교 소방방재학과) ;
  • 박충화 (대전대학교 소방방재학과) ;
  • 고권현 (동양대학교 건축소방행정학과) ;
  • Received : 2010.04.07
  • Accepted : 2010.06.11
  • Published : 2010.06.30
Download PDF
⟨ Previous Next ⟩

Abstract

Experimental and numerical studies were conducted to investigate the thermal and chemical characteristics of heptane fires in a full-scale ISO 9705 room. Representative fire conditions were considered for over-ventilated fire (OVF) and under-ventilated fire (UVF). Fuel flow rate and doorway width were changed to create OVF and UVF conditions. Detailed comparisons of temperature and species concentrations between experimental and numerical data were presented in order to validate the predictive performance of FDS (Fire Dynamic Simulator). The OVF and UVF were explicitly characterized with distributions of temperature and product formation measured in the upper layer, as well as combustion efficiency and global equivalence ratio. It was shown that the numerical results provided a quantitatively realistic prediction of the experimental results observed in the OVF conditions. For the UVF, the numerically predicted temperature showed reasonable agreement with the measured temperature. The predicted steady-state volume fractions of $O_2$, $CO_2$, CO and THC also agreed quantitatively with the experimental data. Although there were some limitations to predict accurately the transient behavior in terms of CO production/consumption in the UVF condition, it was concluded that the current FDS was very useful tool to predict the fire characteristics inside the compartment for the OVF and UVF.

실규모 ISO 9705 표준 화재실에서 과환기화재 및 환기부족화재에 대한 열 및 화학적 특성에 관한 실험 및 수치해석 연구가 수행되었다. 과환기화재 및 환기부족화재의 발생을 위하여 연료 유량과 출입구의 폭이 변화되었다. FDS(Fire Dynamic Simulator)의 화재현상 예측성능을 검토하기 위하여 실험과 수치해석에서 얻어진 온도 및 화학종의 농도에 대한 상세한 비교가 이루어졌다. 과환기화재 및 환기부족화재의 전반적인 특성은 연소효율, 총괄당량비뿐만 아니라 고온 상층부에서 측정된 온도 및 화학종의 농도분포에 의해서도 명확하게 구분되었다. 과환기화재에서 FDS는 온도 및 화학종의 농도에 관한 실험결과를 정량적으로 매우 잘 예측하였다. 반면에 환기부족화재의 경우, 시간 증가에 따른 $CO_2$의 감소 및 CO의 증가와 같은 비정상적 화학적특성의 예측에는 한계가 있음을 알 수 있었다. 그럼에도 불구하고 정상상태 구간의 시간 평균된 온도 및 화학종의 농도는 실험결과를 적절히 잘 예측하였다. 위 결과로 부터 FDS는 과환기 화재 및 환기부족화재의 특성을 예측하는데 매우 유용하게 활용될 수 있음을 알 수 있었다.

Keywords

References

  1. N.P. Bryner, E.L. Johnsson, and W.M. Pittz, "Carbon Monoxide Production in Compartment Fires - Reduced-Scale Enclosure Test Facility", NISTIR 5568, NIST, Gaithersburg, MD(1994).
  2. 고권현, 김성찬, A. Hamins, 유홍선, "환기부족 구회 화재에 대한 FDS 해석 및 검증", 한국화재소방학회논문지, Vol.23, No.5, pp.103-109(2009).
  3. W.M. Pitts, "The Global Equivalence Ratio Concept and the Formation Mechanism of Carbon Monoxide in Enclosure Fire", Prog. Energy Comb. Sci., Vol.21, pp.197-237(1995). https://doi.org/10.1016/0360-1285(95)00004-2
  4. S. Leonard, G.W. Mulholland, R. Puri, and R.J. Santoro, "Generation of CO and Somke during Underventilated Combustion", Combust. Flame, Vol.98, pp.20-34(1994). https://doi.org/10.1016/0010-2180(94)90195-3
  5. R.A. Bryant, "Particle Image Velocimetry Measurements of Buoyancy Induced Flow Through a Doorway", NISTIR 7252, NIST, Gaithersburg, MD (2005).
  6. V. Novozhilov, "Computational Fluid Dynamics Modeling of Compartment Fires", Prog. Energy Comb. Sci., Vol.27, pp.611-666(2001). https://doi.org/10.1016/S0360-1285(01)00005-3
  7. T. Poinsot and D. Veynante, "Theoretical Numerical Combustion", Edwards(2001).
  8. K. McGrattan, S. Hostikka, J. Floyd, H. Baum, and R. Rehm, Fire Dynamic Simulator (Version 5): Technical Reference Guide, NIST SP 1018-5, NIST, Gaithersburg, MD (2007).
  9. J. Smagorinsky, "General Circulation Experiments with the Primitive Equations. I. The Basic Experiment", Monthly Weather Review, Vol.91, No.3, pp.99-164(1963). https://doi.org/10.1175/1520-0493(1963)091<0099:GCEWTP>2.3.CO;2
  10. R.W. Bilger, "Turbulent Diffusion Flames", Annual Review of Fluid Mechanics, Vol.21, pp.101-135 (1989). https://doi.org/10.1146/annurev.fl.21.010189.000533
  11. J.E. Floyd and K.B. McGrattan, "Extending the Mixture Fraction Concept to Address Under-ventilated Fires", Fire Safety Journal, Vol.44, pp.291-300 (2009). https://doi.org/10.1016/j.firesaf.2008.07.002
  12. A. Lock, M. Bundy, E.L. Johnsson, A. Hamins, G.H. Ko, C.H. Hwang, P. Fuss, and R. Harris, "Experimental Study of the Effects of Fuel Type, Fuel Distribution, and Vent Size on Full-scale Underventilated Compartment Fires in an ISO 9705 room", NIST TN 1603, NIST, Gaithersburg, MD (2008).
  13. W. Mell, A. Maranghides, R. McDermott, and S.L. Manzello, "Numerical Simulation and Experiments of Burning Douglas Fir Trees", Combust. Flame, Vol.156, pp.2023-2041(2009). https://doi.org/10.1016/j.combustflame.2009.06.015
  14. J. Smagorinsky, "Gerneral Circulation Experiments with the Primitive Equations", Monthly Weather Rev., Vol.91, No.3, pp.99-1641963). https://doi.org/10.1175/1520-0493(1963)091<0099:GCEWTP>2.3.CO;2
  15. G.D. Raithby and E.H. Chui, "A Finite-Volume Method for Predicting Radiant Heat Transfer in Enclosures with Participating Media", J. Heat Transfer, Vol.112, No.2, pp.415-423(1990). https://doi.org/10.1115/1.2910394
  16. A. Tewarson, "Generation of Heat and Chemical Compounds in Fires", SFPE Handbook of Fire Protecting Engineering, Social Fire Protection Engineers (1995).
  17. K. McGrattan, "Verification & Validation of Selected Fire Models for Nuclear Power Plant Applications", Volume 7: Fire Dynamic Simulator (FDS), Finail Report NUREG-1824, EPRI 1011999(2007).
  18. A. Bounagui, N. Benichou, C. McCartney, and A. Kashef, Optimizing the Grid Size Used in CFD Simulations to Evaluate Fire Safety in Houses, In: 3rd NRC Symposium on Computational Fluid Dynamics, High Performance Computing and Virtual Reality, Ottawa(2003).
  19. K. McGrattan, J. Floyd, G. Forney, H. Baum, and S. Hostikka, "Improved Radiation and Combustion Routines for a Large Eddy Simulation Fire Model", In: Fire Safety Science - Proc. 7th Int. Symp., Worcester, MA, pp.827-838(2003).