MATHEMATICAL-MODELING AND COMPUTER-SIMULATION OF FIRE PHENOMENA

An approach to the study of gas phase combustion and convection proces ses in fires using a combination of mathematical analysis and computer simulation is presented. It seeks to solve the governing equations di rectly (if approximately) by decomposing the fire into a large-scale c onvective and radiative transport problem coupled to a small-scale ''t hermal-element'' model of combustion and radiative emission. The therm al-element model solves the combustion equations in a local Lagrangian coordinate system convected by the large-scale motion, which in turn is driven by the heat released by the combustion processes. The large- scale flow is studied using finite-difference techniques to solve larg e-eddy simulations of the Navier-Stokes equations. The basic theory be hind the methodology is outlined and sample results of both large- and small-scale phenomena are presented. An analytical model of a large e ddy is used to show how the simulation can be assembled to yield radia tion feedback from a fire plume to a target surface.