- Author
-
Ulrich, R. D.
|
Butcher, A. G.
- Title
- Post-Ignition Burning of Horizontal Wood Surfaces.
- Coporate
- Naval Weapons Center, China Lake, CA
- Sponsor
- Naval Air Systems Command, Washington,DC
- Report
-
NWC-TP-5271
November 1971
24 p.
- Distribution
- Available from National Technical Information Service
- Contract
- N66001-70-C-1068
- Keywords
-
wood
|
ignition
|
combustion
|
wind velocity
|
preignition
|
smoke production
- Identifiers
- radiation source; controlled wind; post-ignition combustion; burn time
- Abstract
- The effects of wind speed control and variable radiation input on the ignition and continued burning of horizontally mounted white pine wood pieces were investigated. The wind velocity and radiation energy input were varied before and after ignition in programmed sequences. The input flux reduction caused by pre-ignition smoke production was predictable upon knowing the wind velocity. Ignition times decreased slightly with moderate wind, and ignition was prevented with wind velocities above 6 ft/sec when the heat flux was 2.4 cal/cm2-sec. Measurements made with a calorimeter mounted in the test samples indicated that the flame intensity increased with continued burning. Flame radiation intensity was also dependent on the amount of wind, reaching a maximum with a velocity of 2 to 4 ft/sec. Measurements made to determine the amount of energy required to sustain burning after ignition indicated a minimum amount and a rate of energy input necessary for any given time of continued combustion. The rate measured was lower than the average flame intensity of 0.95 cal/cm2-sec, but losses due to heat flow from the wood lowered the net effect of the flame to below the required limit of 0.667 cal/cm2-sec, and the flame alone could not sustain burning.