Application of a Statistical Narrow Band Model to CFD Modelling of Upward Flame Spread Over PMMA Walls

Abstract

A statistical narrow band (SNB) radiation gas model has been incorporated into a Reynolds-averaged Navier-Stoke (RANS) based computational fluid dynamics (CFD) code. The coupled CFD code is used in this work to simulate two upward flame spread scenarios: the first one concerns flame spread over a vertical PMMA wall, while the other represents flame spread along vertical corner walls. For comparison purpose, the weighted-sum-of-greygases (WSGG) model was also used. Simulation results indicate that the CFD model is capable of predicting reasonably the flame spread phenomenon over simple materials such as PMMA. Compared to the WSGG approach, the SNB model generally yields more accurate results thanks to a better predicted gas flow field which in turn improves the prediction of the radiative heat fluxes imposed on solid surfaces and consequently that of the flame spread rate and heat release rate.