Numerical Simulation of Opposed Flow Flame Spread over a Thermally Thick Solid Fuel

Abstract

The opposed flow flame spread over a thermally thick solid fuel has been modelled by means of the gas phase unsteady two-dimensional balance equations for chemical species and energy coupled to the unsteady two-dimensional energy balance for the solid fuel. Finite gas phase kinetics and solid phase pyrolysis with an Arrhenius form are included. The solution is performed numerically by a semi-implicit finite difference method. The flame structure and the behaviour of the solid phase are predicted and discussed as a function of the opposed flow rate and of the shape of the velocity profile. Qualitative agreement is obtained with previous theoretical studies and with experimental data. The detailed description of the solid phase temperature Geld has allowed to suggest an explanation for the observed decrease of the spread rate when increasing the opposed flow rate.