- Author
-
Fernandez-Pello, A. C.
- Title
- Fire Propagation in Concurrent Flows. Final Progress Report. June 1, 1982-May 31, 1983.
- Coporate
- California Univ., Berkeley
- Sponsor
- National Bureau of Standards, Gaithersburg, MD
- Report
-
NBS GCR 83-437,
July 1983,
77 p.
- Distribution
- Available from National Technical Information Service
- Contract
- NB0NADA1064
- Keywords
-
burning rate
|
flame spread
|
heat transfer
|
natural convection
|
polymethyl methacrylate
|
polyoxymethylene
|
pyrolysis
|
oxygen concentration
- Abstract
- A study has been performed of the process of fire spead in gaseous flows moving in the direction of flame propagation, i.e.: 1) Natural convection, flow assisted, flame spread over enclosure's walls; 2) Flame spread over a flat surface in a concurrent forced flow. During this reporting period, a numerical analysis has been performed of the natural convection, steady burning of combustible surfaces of varied length and composition forming the walls of an enclosure. The results for the location and length of the flame agree well with experimental data. In a concurrent analytical effort, an analysis has been developed of the mixed convective burning of surface with arbitrary inclination. The analysis provides explicit expressions for the mass burning rate as a function of the mixed convection parameter [Re x(n) + Gr x(m)](1/2n) and the mixed convection ratio [Gr x (m)/Re x(n)](1/2). Experimentally, measurements of the rate of flame spread in a concurrent forced flow of varied velocity and oxygen concentration show that the spread process is controlled primarily by heat transfer from the flame to the fuel. The measured rate of spread of the pyrolysis front, Vp, can be correlated in terms of the free stream gas velocity [equation omitted], and mass transfer number B, by using an expression of the form [equation omitted], which agrees with the predictions of thermal theories of the flow assisted mode of flame spread.