Two-dimensional model of heat transfer in a pine trunk under the influence of a forest fire environment

Abstract

This paper presents a study on two-dimensional model of heat transfers in a pine tree trunk under the influence of a forest fire environment. In this study, a thermal response model of the tree trunk was developed, starting from a geometric model of complex topology of the trunk obtained using mesh generation. The thermal response model of the tree trunk is founded on energy and mass equations. In energy equations, heat exchanges are considered by conduction inside the tree trunk, by convection between the outside surface of the tree trunk and the surrounding environment and by radiation between the outside surface of the tree trunk and the surrounding area including the fire front. The heat exchanges by radiation between the tree trunk and the fire front are calculated using view factors obtained taking into account the geometric model of the tree trunk. In the numerical simulation, the forest fire environment is represented by a fire front, 10 m wide and 1 m high, which moves, with an inclination of 45º, at a constant speed. The numerical results of the temperature distribution tree trunk were obtained for a wind speed of 5 m/s and an average flame temperature of 500ºC. These results allow us to locate the tissues of the tree trunk that will reach lethal conditions.