Large eddy simulation of room fire spread using a medium scale compartment made of medium density fibreboard (MDF) panels

At present, there is a shortage of experimental and simulation studies on fire spread in medium- and large-scale compartments while the existing models of the fire spread are limited for typical engineering applications. This paper proposes a new model for large-scale fire spread on medium density fibreboard (MDF) panels. Validating the model with single burning item (SBI) experiments, it is found that the numerical simulation closely predicts the experimental heat release rate (HRR) with some error near the peak. The predicted heat flux and distance of lateral flame spread are consistent with the experiments and an existing model. The effects of kinetic properties and heat of combustion are identified through a sensitivity analysis. The decrease of activation energy and increase of pre-exponential factor make the MDF easier to pyrolyze and the increase of heat of combustion enhances the flame temperature and thus provide more heat feedback to the sample surface. The low activation energy (71.9 kJ/mol) and high heat of combustion (46.5 MJ/kg) of the model ensure the occurrence of flame spread. Furthermore, the model was validated using medium-scale compartment fire experiments and the results showed that the model can accurately predict the HRR after flashover (the error is within 7%). While the burner is ignited, the predictions of in-compartment gas temperature and heat flux are more accurate. However, when the burner is extinguished, the modelled in-compartment gas temperature is lower than the experimental values, resulting in a lower heat flux prediction. The model leads to easier flame spread; therefore, the modelled flame spreads faster in the compartment compared to the experiment, and thus the HRR increases more rapidly.