On the experimental determination of flame front positions and of propagation parameters for a fire

This work proposes a new method for determining the fire front positions for optically thin flames and the rate of spread (ROS) of forest or vegetation fires. It is based on an application for linear flame fronts that are generated in a fire tunnel with known dimensions using Quercus coccifera shrubs as vegetal fuel. In the first step of the method, the heat fluxes coming from the flame are measured by a specific thermal sensor in four horizontal directions. In the second, these heat fluxes are calculated theoretically using an approximate resolution of the radiative transfer equation. Subsequently, the positions of the fire front and the flame characteristics are determined by applying an inverse method. The rate of spread is deduced by applying a least-square regression on the position values. An extrapolation of this new method to more complex experimental scenarios such as prescribed burnings is proposed.