A MULTISCALE FULL-SPECTRUM k-DISTRIBUTION METHOD FOR RADIATIVE TRANSFER IN NONHOMOGENEOUS GAS-SOOT MIXTURES WITH WALL EMISSION

The multiscale full-spectrum k-distribution (MSFSK) method has become a promising method for radiative heat transfer in in homogeneous media. The scope of the MSFSK method has been limited to radiation calculations involving inhomogeneous gas mixtures only. The objective of this paper is to develop a MSFSK model that is accurate for inhomogeneous mixtures of both gases and nongray particles, such as soot. Soot is added as one more scale in addition to the gas scales. The overlap parameters between scales are calculated by mixing molecular gases with soot particles at the narrowband level. This MSFSK method is also capable of black/gray wall emission. Because wall emission is continuous over the spectrum, similar to radiation from soot, wall emission is treated with in the soot scale. Sample calculations are performed for a one-dimensional medium with step changes in species concentration and temperature and also for a two-dimensional axisymmetric medium involving combustion of methane. The MSFSK method is observed to accurately predict heat transfer from inhomogeneous gas-soot mixture with/without wall emission yielding close to line-by-line accuracy with several orders of magnitude less computational cost.