Numerical Predictions on the Soil Thermal Effect Under Surface Fire Conditions

Abstract

A control volume numerical method is used to predict the temperature distribution inside a soil extent, the surface of which has been swept by a two-dimensional flame front with pre-defined velocity and temperature distributions. Natural and forced convection, as well as radiation effects are included in the specification of the soil surface thermal boundary condition. The flame residence time and maximum temperature are identified as two major parameters to characterize the flame front. As expected, the heat penetration depth is confined to the near vicinity of the soil surface. Moreover, horizontal heat conduction throughout the soil has not always a significant effect on its global, transient temperature distribution. The influence of wind velocity and of soil thermal diffusivity upon its temperature distribution are analysed. Radiation is the dominant contribution in the whole heat transfer process between flame and ground surface.