Numerical calculation of effective emissivities of diffuse cones with a series technique.

Effective emissivities of conical cavities having diffuse surfaces are computed by an iterative procedure and effective reflectances from series that involve powers of the reflectance of the wall material. If reflections after the nth are neglected in the computation, an upper bound for the truncation error in the effective reflectance is 1.2p(n+1)I(n+1)/(l - p) for cone half-angles between 3.75 and 60 degrees and for 5 </= n, where p is the surface reflectance and I(n+1) is the (n + l)th-order coefficient of the effective reflectance.