Heat Transfer Engineering

Chapter 8: Thermal radiation

Abstract

This chapter first introduces the basic ideas of radiation. Solid geometry is briefly discussed. The concept of a black body is introduced, followed by a formal definition of spectral directional intensity, as well as hemispherical and total hemispherical emissive powers. The Planck’s distribution is then introduced and from this, the Wien’s displacement law and Stefan-Boltzmann law are derived. Emissivity is defined for a real surface and this is followed by introduction of reflectivity, absorptivity, and transmissivity. The enclosure theory is next introduced. To use this, the idea of view factor is introduced, followed by view factor algebra. The radiosity-irradiation method is presented to calculate the ...