Implicitly Coupling Heat Conduction Into a Zone Fire Model.
Implicitly Coupling Heat Conduction Into a Zone Fire
Moss, W. F.; Forney, G. P.
NISTIR 4886; 34 p. July 1992.
Available from: National Technical Information Service
Order number: PB92-222769
conductive heat transfer; fire models; zone models;
equations; computer models; algorithms
This report examines several methods for coupling the
partial differential equations that arise in conductive
heat transfer with the ordinary differential equations
that arise in zone fire modeling. Two existing
algorithms (method of lines and time splitting) are
discussed and a new strategy is proposed for performing
this coupling. This strategy couples the wall surface
temperature rather than the entire wall temperature
rpofile with the other zone fire modeling solution
variables by requiring that the wall surface temperature
gradient and the incident heat flux (sum of convective
and net radiative flux) satisfy Fourier's law. Two
prototype fire models were written to test the ideas
discussed in this report. The first, CONRAD1,
implements the method of lines strategy for solving heat
conduction. The second, CONRAD2, implements the new
strategy. Though inefficient, CONRAD1 uses will
established numerical techniques and therefore serves as
a benchmark to test the numerical ideas implemented in
CONRAD2. Both programs use the stiff
differential-algebraic equation solver DASSL. Supporting
numerical results are presented.