Parametric study of the heat transfer coefficient in bi-dimensional smoldering simulation

In this paper, we present the transient modeling results of 2-D forward smoldering in a cylindrical configuration filled with a foam porous material. The objective of the study is to explain the effect of the heat losses from lateral boundaries in the front smolder propagation. The developed numerical code is capable of predicting the fire initiation and the smoldering (slow-burning) characteristics of foam insulation materials. The finite volume discretization and the bi-conjugate gradient stabilized method are used to solve the system governing equations. The chemical kinetics model is based on a first order pyrolysis reaction, followed by oxidation of the porous fuel and the carbonaceous char residual. This second oxidation reaction might promote the transition from smoldering to flaming and thus fire initiation. The gas and solid temperature, and the oxygen and the char mass fraction two-dimensional temporal evolutions are computed. Different heat and mass transfer coefficients are used to simulate the heat losses to the surrounding. Non-reacted foam regions are observed near the side wall, confirming experimental observations. The base case is chosen to represent the experimental conditions reported in the literature. The numerical predictions show very good agreement with the published experimental and 1-D numerical results