ABSTRACT
The main part of this chapter is devoted to the field of radiative transfer, especially in the infrared part of the spectrum. The other two modes of heat transfer, namely, conduction and convection, are discussed much more concisely. The microscopic aspects involved in the three modes of transfer are recalled briefly. Purely numerical methods of resolution based on discretization of space and time are often preferred for complex situations. Powerful software packages are commercially available, however a learning time should be taken into consideration since it is necessary for efficient use. Energy transfer by radiation is a common experience. Some quantities must be defined in order to quantify the radiation leaving or reaching a surface. Moreover, scattering inside the material can increase its reflectivity because of the multiple reflections induced by the microstructure. Direct methods apply emissivity definitions: the radiance (or emissive power) of the material is measured and its ratio to that of a blackbody is calculated.
