NUMERICAL PREDICTIONS ON THE SOIL THERMAL EFFECT UNDER SURFACE FIRE CONDITIONS

A control volume numerical method is used to predict the temperature d istribution inside a soil extent, the surface of which has been swept by a two-dimensional flame front with pre-defined velocity and tempera ture distributions. Natural and forced convection, as well as radiatio n effects are included in the specification of the soil surface therma l boundary condition. The flame residence time and maximum temperature are identified as two major parameters to characterize the flame fron t. As expected, the heat penetration depth is confined to the near vic inity of the soil surface. Moreover, horizontal heat conduction throug hout the soil has not always a significant effect on its global, trans ient temperature distribution. The influence of wind velocity and of s oil thermal diffusivity upon its temperature distribution are analysed . Radiation is the dominant contribution in the whole heat transfer pr ocess between flame and ground surface.