PMMA壁面の上方向への燃え拡がりのLarge eddy simulation

Abstract

A fully coupled fluid-solid approach for flame spread simulations has been developed using FireFOAM. Radiative heat transfer and soot treatment are fully coupled with the pyrolysis calculations. For gaseous combustion, the newly extended eddy dissipation concept (EDC) for the large eddy simulation (LES) is used. Due to low Reynolds number, the laminar combustion model based on viscous diffusion is presented and coupled with the EDC model. The soot model is based on the laminar smoke point concept recently extended to turbulent fires using the partially stirred reactor (PaSR) concept. For radiation, the finite volume discrete ordinate method (FVDOM) is used with the gaseous absorption coefficients evaluated using the polynomial coefficient of temperature. In the solid region, one dimensional diffusion equation for sensible enthalpy is solved. The effect of in-depth radiation is taken into account using the relatively simple formation according to Beer's law. The Arrhenius type pyrolysis model developed by FM Global is used along with their measurements of the PMMA physical properties as input data. The validation study has been conducted with the published experiment. The predictions are in very good agreement with the relevant experimental data, demonstrating that the present modelling approach can be used to predict upward flame spread over PMMA with reasonable accuracy. Such a fully coupled predictive tool can be used to aid fundamental studies of the flame spread phenomena such as investigating the effects of width, inclination angles and side walls on flame spread.