- Author
-
Pitz, W. J.
- Title
- Structure, Inhibition and Extinction of Polymer Diffusion Flames.
- Coporate
- California Univ., Berkeley
- Sponsor
- Department of Energy, Washington, DC
- Report
-
NBS GCR 83-436,
July 1983,
123 p.
- Distribution
- Available from National Technical Information Service
- Contract
- NB805180
- Keywords
-
bromine
|
diffusion flames
|
flame extinguishment
|
flame structure
|
halogens
|
polyethylenes
|
polymers
|
oxygen concentration
- Abstract
- Composition and temperature profiles for combustion of high-purity polyethylene polymer in the opposed flow of a gaseous oxygen-nitrogen stream were obtained to examine the flame structure near extinction. As the oxygen concentration in the oxidizer flow was reduced, the flame moved toward the surface, the position of unity equivalence ration moved away from the surface, and the maximum flame temperature decreased. Surface oxidation reactions were of minor importance. Halogenated inhibition effectiveness was assessed by evaluating its influence on extinction limits. The order of increasing effectiveness was found to be chlorine in the oxidizer flow, chlorine in the polymer, and bromine in the bromine in the oxidizer flow. Predictions from a stagnation boundary-layer model with either a one-step, Arrhenius-rate expression or a flame-sheet representation were compared to the measured structure. Penetration of oxygen through the flame was accurately predicted by a finite-rate model. The temperature dependences of the global reaction rates at extinction were largely unaffected by addition of the halogen inhibitors.