Optical Constants of Soot and Their Application to Heat-Flux Calculations

Abstract

Data on the room temperature optical constants of soot are presented for the wavelength regions 0.4–0.8μ and 2.5–10.0/μ. Dispersion formulas are developed for interpolating the data between 0.8 and 2.5μ. The results are used to calculate the spectral absorption coefficient and the total emissivities of soot suspensions. It is shown that the correct values of the optical constants are needed in the use of light-scattering techniques for the measurement of the soot concentration but that uncertainties introduced in flux calculations by use of approximate values of the optical constants are not greater than those introduced by the present uncertainties in the values of the soot concentration.