Spectral emittance of particulate ash-like deposits: Theoretical predictions compared to experimental measurement

This note presents results of a theoretical and experimental investigation on the emittance of particulate deposits. A simple model based on independent and multiple scattering and using discrete ordinate method has been developed to predict the spectral hemispherical and normal emittance of particulate deposits. The model predictions are compared with measurements carried out under this study-controlled spectral emission measurements between wavelengths of 2 and 12 mum on deposits of ground synthetic ash particles having known composition and particle size. The trends from the predictions matched well with the measured values, except for some differences in the wavelength region below 4 mum, and between 8 mum and 12 mum wavelength. Possible reasons for these differences are discussed.