- Author
-
Borgeson, R. A.
- Title
- Flame Spread and Spread Limits. Final Report June 19, 1981-June 18, 1982.
- Coporate
- Case Western Reserve Univ., Cleveland, OH
- Sponsor
- National Bureau of Standards, Gaithersburg, MD
- Report
-
NBS GCR 82-396,
July 1982,
57 p.
- Distribution
- Available from National Technical Information Service
- Contract
- NB80NADA1017
- Keywords
-
additives
|
computer models
|
flame spread
|
pyrolysis
|
solid fuels
- Abstract
- The computer model of Frey and T'ien (1979) has been extended to study the effects of the initial bulk fuel temperature and an inert additive. The theory assumes a thermally thin solid in an opposed flow with negligible forward heat conduction in the fuel. Raising the initial fuel temperature was found to increase the flame spread rate by augmenting the fuel mass flux in the forward part of the pyrolysis zone. As the initial fuel temperature increases, the limitimg value of the Damkohler number for extinction decreases. An inert additive reduces the spread rate by lowering the flame temperature and wasting energy in the inert pyrolysis. The effect of the inert additive's pyrolysis kinetic parameters was found to be small. The flame spread rate is roughly correlatable to the fraction of energy entering the solid which is expended in the inert pyrolysis, QI/QT. As QI/QT increases, extinction occurs at a higher Damkohler number.