ABSTRACT
In phenomenological heat conduction studies, however, the molecular structure of the medium is disregarded and the medium is considered to be a continuum. In a fissionable material, internal energy is generated as a result of nuclear reactions which consist of continuous changes in the composition of the material as fissionable material is turned into internal energy. The chapter provides the boundary conditions into the following categories: prescribed boundary temperature, prescribed heat flux, heat transfer by convection, heat transfer by radiation, and interface conditions. The hypothesis of an instantaneous response of the heat flux to a temperature gradient, intrinsic to the classical Fourier's law, may fail for some special applications. Such as in heat transfer at the nanoscale and heat conduction problems related to very short time scales, such as in fast pulsating laser heating and rapidly contacting surfaces in electronic devices.
