The Emission of Radiation from Diatomic Gases. I. Approximate Calculations

Abstract

An approximate method for estimating radiant heat transfer from gaseous emitters is proposed. An average absorption coefficient is used for the effective width of an entire vibration‐rotation band. The procedure for determining an average absorption coefficient in terms of the integrated absorption is justified, approximately, for very small optical densities and also for large total pressures where the spectral half‐width is no longer small compared with the rotational spacing. Because of these limitations it is to be expected that the procedure proposed here will be particularly useful only in estimating gaseous emissivities for emitters in high‐pressure combustion chambers. A preliminary compilation is given of the theoretical results which are necessary for making rapid estimates of the emissivities, over a wide temperature range, for CO, HI, HBr, HCl, and HF.