K-DISTRIBUTION ANALYSIS OF GAS RADIATION WITH NONGRAY, EMITTING, ABSORBING, AND ANISOTROPIC SCATTERING PARTICLES

The K-distribution technique is presented for predicting nongray gas r adiation in the presence of particle scattering. This technique transf orms the otherwise formidable spectral integration problem from the fr equency domain to the K or gas absorption coefficient domain. This tra nsformation is made possible by the negligible variation of blackbody intensity and particle radiative properties with frequency within a ga s band. Application of the K-distribution technique to an isothermal e mission problem is made. Results are compared with those from the Mont e-Carlo method. These results show that, with the K-distribution techn ique, the detailed absorption line structure within a gas band as well as the scattering effect due to particles can be simulated with great numerical accuracy and computational efficiency. Essentially, line-by -line accuracy is achieved without line-by-line spectral integration.