- Author
- Fernandez-Pello, A. C.
- Title
- Fire Propagation in Concurrent Flows. Final Progress Report. Appendix A. August 1, 1987-July 31, 1988.
- Coporate
- California Univ., Berkeley
- Sponsor
- National Institute of Standards and Technology, Gaithersburg, MD
- Report
- NIST GCR 89-560, February 1989, 41 p.
- Distribution
- Available from National Technical Information Service
- Contract
- NIST-GRANT-60NANB7D0737
- Keywords
- air flow | flame length | flame spread | polymethyl methacrylate | pyrolysis
- Abstract
- The research tasks completed during this reporting period include an experimental study of the effect on the spread of flames of the turbulence intensity of an opposed air flow, and a theoretical analysis of the concurrent spread of flames over thin fuels. Both studies are in our opinion important contributions in the study of the flame spread process. The results of the experimental study show that the flame spread process is significantly affected by the flow turbulence intensity for flames spreading over both thin and thick fuels. For a fixed flow velocity, the spread rate decreases as the turbulent intensity is increased. This appears to be due to the turbulent convective cooling of the fuel surface and gas in the vicinity of the flame turbulent convective cooling of the fuel surface and gas in the vicinity of the flame front. Also observed is that extinction of the flames occurs at lower velocities as the turbulent intensity increases. The results of the theoretical analysis, which are in good agreement with previous experimental measurements, give detailed information about the flame structure and mechanisms of flame spread. It is shown that the flame length and consequently the rate of flame spread, are strongly dependent on the interaction between the pyrolysis and burn-out fronts.