A Novel Fast Wavenumber Selection Scheme for Line-by-Line Monte Carlo Simulations of High-Temperature Gases

Implementing line-by-line absorption spectra in the Monte Carlo method provides benchmark solutions for radiative heat transfer in participating media. It is, however, a computationally demanding calculation, and therefore its application is limited to small and medium-scale cases. In gas mixtures, one of the most time-consuming parts is the wavenumber selection for each emission bundle (also known as photon). Due to interdependency of spectral emission of individual species, trial-and-error is needed to obtain the emission wavenumber of species. Doing trial-and-error with tight convergence threshold through large set of data increases the simulation time. This paper presents a novel scheme to select the wavenumber by adding a new dataset which circumvents the need for trial-and-error. The performance of the new scheme is exhibited in four different test cases containing CO₂, H₂O, and CO. An excellent agreement was observed between the results of the new and old schemes. Compared to the previously published hybrid selection scheme, the wavenumber selection is around seven times faster using the new scheme.