FLAMELET-BASED SMOKE PROPERTIES FOR THE FIELD MODELING OF FIRES

Simplified soot formation models are developed for two fuels-propylene and methylmethacrylate-representative of the pyrolysates derived from burning polymer.ic materials in compartment fires. The models incorpo rate descriptions of the key processes of soot particle nucleation, co agulation and surface growth and introduce fuel-dependent model coeffi cients which are established through detailed comparisons between lami nar diffusion flame experiment and computational prediction. A laminar flamelet approach is employed to simplify the computation of the scal ar fields for composition and temperature. For purposes of model evalu ation and calibration, detailed property maps are constructed in the t wo flames for mixture fraction, using probe sampling and mass spectrom etric analysis, temperature by fine wire thermocouple and soot volume fraction by laser extinction. The level of complexity introduced refle cts the compromise between the physical mechanisms described and the c omputational demands of the target application to the improved field m odelling of fires. (C) 1998 Elsevier Science Ltd. All rights reserved.