Abstract
The emissivity of a unit area of the opening of a cavity ∊c is a function of its geometry as well as of the emissivity of its walls ∊0.
If fn is a fraction of incident radiation which is reflected n times before emerging from the cavity, then ρc=∑fnρ0n is the reflectance, and ∊c=1−ρc is the effective emissivity. Under diffuse reflection f1=∫F2dA/∫FdA, where F is the viewfactor from cavity wall to open space. If fn=(1−f1)n−1f1 then ∊c=∊0/[∊0+f1(1−∊0)]. The approximation is good in the domain of low reflectivity. The f1 have been calculated for a variety of cavity shapes.
© 1963 Optical Society of America
Full Article | PDF ArticleMore Like This
R. E. Bedford and C. K. Ma
J. Opt. Soc. Am. 64(3) 339-349 (1974)
R. E. Bedford and C. K. Ma
J. Opt. Soc. Am. 65(5) 565-572 (1975)
E. M. Sparrow and V. K. Jonsson
J. Opt. Soc. Am. 53(7) 816-821 (1963)