Document Type : Special Issue Manuscripts
Laboratory of Thermal and Energy Systems Studies, National Engineering School of Monastir, Monastir University, Monastir, Monastir, 5019, Tunisia
Smoldering phenomenon can be described as a slow, low-temperature, flameless form of combustion,
sustained by heterogeneous reactions with oxygen occurring at the surface of a condensed-phase fuel. In this
work a computational study on the smoldering ignition and propagation in polyurethane foam is carried out.
First, we investigated numerically the heat transfer and the fluid flow in porous media using the generalized
lattice Boltzmann method (LBM). Our appropriate code is validated through the study of a thermal injected
flow. LBM results are compared to analytical solutions and numerical results obtained using the Finite
Difference Method. Second, the numerical model is extended to account for chemical reactions. We introduce
the two-dimensional, transient, governing equations for smoldering combustion in a porous fuel. The model
describes opposed and forward propagation according to appropriate assumptions. The kinetics model is
based on a three-step mechanism. The temperature and char mass fraction profiles are studied at different
cross-sections. Obtained results are compared to literature solutions. At the beginning, the important quantity
of char is produced near the ignited boundary. To follow the phenomenon, the isotherms are presented at
different instants. The results reproduce the features of the smoldering process and represent a significant step
forward in smoldering combustion modeling.