Molecular Gas Band Radiation in Cylinders

Abstract

The radiative heat flux in a molecular gas within a cylinder is formulated in terms of an axial band absorptance. The axial band absorptance function is used to reduce the two angular, one spatial, and one spectral integrals encountered to one angular and one spatial integral such as is encountered in radiative transfer problems with spherical symmetry. A closed form is obtained for the axial band absorptance for the exponential-winged band model. Illustrative results are presented for a cylindrical gas volume with trapezoidal, parabolic, or Gaussian temperature profile. Mean beam length, absorptivity, and emissivity of a cylinder of gas are obtained as a function of the optical depth at the band head.