Heat Transfer

Abstract

The heat from fires influences fire behavior and effects on plants, animals, people, and their homes. How? In this chapter, we explain heat transfer by radiation, convection, conduction, and mass transport using the equations for the physical processes and simple, applied examples. All chemical reactions in flaming and smoldering combustion are accompanied by the transfer of energy as heat by radiation, conduction, convection, and mass transport. For a fire to be sustained, the heat energy released during the combustion of the fuel must be transferred to unburned fuel, and there needs to be enough heat for unburned fuel to ignite if the fire is to advance. Also, a part of that energy released by the fuel will move downwards into the soil or upwards into the canopy and the atmosphere. Mass transport occurs when winds carry burning fuels to unburned fuels where they can ignite and thus accelerate fire spread. While most heat transfer in fires is by some combination of convection, radiation, conduction, and mass transport, we discuss which dominates in particular situations. Four interactive spreadsheets reinforce lessons learned. In later chapters of our book, Fire Science From Chemistry to Landscape Management, we relate these heat transfer processes to the effects fires can have on people, plants, animals, soils, and ecosystem processes and what we can do to manage those effects.