Document


Title

Burning rate and flow resistance through porous fuel beds: axisymmetric versus line fires
Document Type: Journal Article
Author(s): Sara S. McAllister
Publication Year: 2022

Cataloging Information

Keyword(s):
  • airflow
  • axisymmetric fire
  • burning rate
  • crib fires
  • laboratory fires
  • line fire
  • wildfire
  • wildland fire
Topic(s):
Record Maintained By:
Record Last Modified: January 11, 2022
FRAMES Record Number: 65099

Description

The burning rate of wildland fuels is a poorly understood yet key fire behavior metric. Previous work has utilized wood cribs; however, it has not yet been addressed whether the burning behavior of a crib, an axisymmetric fire, can be representative of a line fire, a typical configuration in wildfires. In this study, airflow into two sides of the crib was physically blocked and the resulting burning rate was noted. Six crib designs with a range stick thicknesses and porosities were tested both on the ground and with a gap underneath. For most cases, blocking the sides had only a modest effect on the burning rate (up to 22% reduction). In these cases, axisymmetric fire sources may give an acceptable approximation for the burning rate of a segment of a line fire. However, for the cribs built with thinner sticks placed directly on the ground, the reduction was more dramatic (up to 45%) and the use of axisymmetric and line fire sources requires further consideration. Resistances to flow in both the horizontal and vertical directions within the crib were used to understand these trends and to provide a better qualitative picture of how flows govern the burning of cribs in general.

Online Link(s):
Citation:
McAllister, Sara. 2022. Burning rate and flow resistance through porous fuel beds: axisymmetric versus line fires. Combustion Science and Technology online early.