Application of the statistical narrow-band correlated- k method to non-grey gas radiation in CO 2–H 2O mixtures: approximate treatments of overlapping bands

Abstract

The statistical narrow-band correlated- k method was employed to calculate narrow-band intensities along a line-of-sight and radiative transfer in a three-dimensional rectangular enclosure containing nonisothermal CO 2–H 2O–N 2 mixtures at 1 atm. The correlated treatment of overlapping narrow bands of CO 2 and H 2O based on the multiplication property of gas transmissivity significantly increases the execution time of this method at each overlapping band. Three new approximate treatments for overlapping bands were proposed to improve the computational efficiency of the statistical narrow-band correlated- k method for gas radiation calculations in media containing two or more radiating gases. The accuracy of the statistical narrow-band correlated- k method using four approximate treatments of overlapping bands in CO 2–H 2O–N 2 mixtures was evaluated by comparing their numerical results with those obtained using the correlated treatment of overlapping bands. Such comparisons were made for both spectrally integrated quantities and narrow-band intensities along a line-of-sight. Results of the statistical narrow-band model were also obtained as a reference solution in the evaluation of the results of the statistical narrow-band correlated- k method.