Band models for nonisothermal radiating gases.

Approximate relations are presented for calculating the mean spectral distribution of the net radiance at the boundary of a nonisothermal gas, given the distributions of temperature, pressure, and composition within the region and the appropriate experimental spectral absorptance data. Experimental data obtained for the 2.7-micro bands of H(2)O, in which variations in temperature between 900 degrees K to 1200 degrees K were imposed along a 60-cm path at various pressures, are compared with calculations based on a strongline model. A more general band model expression is proposed for intermediate optical depths.