Gray Surface Heat Transfer. ϵ 2 emissivity of plate 2. For a surface that is gray and opaque ie.
Finally the radiative heat transfer for a grey body can be represented as a resistance as seen from the equation below. Eq 4 rfrac1 εεa equation 3 shows you how to calculate the total radiative heat transfer when thermal radiation strikes a grey body. In this blog post we discuss surface to surface radiation theory for the so called gray body how to implement it in the comsol multiphysics software and an interesting use of this theory.
Schematic of a thermos wall.
Even though the first man made light source used thermal radiation the effect wasnt fully understood until the discovery of quantum mechanics. The surface temperatures are θ 1 40 c and θ 2 5 c respectively. Therefore only consider surface to surface radiation for numerical analysis. In general 6.