- Author
-
Kulkarni, A. K.
|
Hwang, J.
- Title
- Model for Vertical Wall Fire in a Stratified Atmosphere.
- Coporate
- Pennsylvania State Univ., University Park, PA
- Sponsor
- National Bureau of Standards, Gaithersburg, MD
- Report
-
NBS GCR 86-510,
March 1986,
62 p.
- Distribution
- Available from National Technical Information Service
- Contract
- GRANT-60NANB4D0037
- Keywords
-
fire models
|
laminar burning
|
pyrolysis models
|
walls
- Abstract
- A comprehensive mathematical model is presented for understanding the characteristics of a burning vertical wall immersed in a quiescent ambient atmosphere having a nonuniform vertical distribution of temperature and oxidizer mass fraction. Such a stratified atmosphere occurs, for example, in the interior of a room or aircraft cabin on fire. A set of partial differential equations and suitable boundary conditions describing a laminar flow of exothermically reacting species is solved using the Keller Box finite difference scheme. Results of burning rate and flow parameters (such as the maximum vertical velocity, flame position, etc.) are presented for many different cases of stratified atmosphere. A comparison of these results with the results for the nonstratified atmosphere shows that the predicated burning rate for a thermally stratified case behaves like a linear combination of results for the corresponding nonstrtified cases; however, this does not hold for compositionwise stratified atmosphere. The stratification has a substantial nonlinear effect on the flow structure in the wall fire. Different possibilities for surface reradiation models are also discussed.