Advanced Heat Transfer: Thermal Radiation, Thermal Radiation, Blackbody, Kirchhoff, Plank and Wien’s displacement Laws, View Factor, Radiation Exchange and more.
We start this course with a discussion of electromagnetic waves and the electromagnetic spectrum, with particular emphasis on thermal radiation. Then we introduce the idealized blackbody, blackbody radiation, and blackbody radiation function, together with the Stefan–Boltzmann law, Planck’s law, and Wien’s displacement law.
Radiation is emitted by every point on a plane surface in all directions into the hemisphere above the surface. The quantity that describes the magnitude of radiation emitted or incident in a specified direction in space is the radiation intensity. Various radiation fluxes such as emissive power, irradiation, and radiosity are expressed in terms of intensity. This is followed by a discussion of radiative properties of materials such as emissivity, absorptivity, reflectivity, and transmissivity and their dependence on wavelength, direction, and temperature. The greenhouse effect is presented as an example of the consequences of the wavelength dependence of radiation properties.
We then discuss view factors and the rules associated with them. View factor expressions and charts for some common configurations are given, and the crossed-strings method is presented. We then discuss radiation heat transfer, first between black surfaces and then between nonblack surfaces using the radiation network approach. We continue with radiation shields and discuss the its radiation effects.
