Development of a Model for the Heat Release Rate of Wood: A Status Report.
Development of a Model for the Heat Release Rate of
Wood: A Status Report.
Parker, W. J.
NBSIR 85-3163; 108 p. May 1985.
Sponsor:Federal Emergency Management Agency, Washington, DC
Available from: National Technical Information Service
Order number: AD/A-160275
heat release rate; wood; pyrolysis; heat of combustion;
thermal conductivity; computer models
This report describes the status of the development of a
method for predicting the heat release rate of wood for
different thicknesses, moisture contents, and exposure
conditions. A computer model has been set up on a
microcomputer. Experimental techniques have been
devised to obtain the imput data required by the model.
These include (1) the thermal conductivity as a function
of temperature and percent loss, (2) the kinetic
constants needed to describe the mass loss rate, (3) the
heat of combustion of the volatile pyrolysis products,
and (4) the contraction factors due to charring.
Sufficient data on these parameters were taken to
exercise the model. Heat release rates and effective
heats of combustion were measured as a function of
external radiant flux on 12.5 mm thick dry vertical
specimens of Douglas fir particle board. The calculated
and measured peak heat release rate curves are similar
in shape and amplitude but differ significantly in time
scale. This may be due to the lack of thermal
conductivity data on the char in the high temperature
range. There is very good agreement between the
calculated and measured effective heats of combustion.
The initial results with the model are promising.