Radiative properties of char, fly-ash, and soot particles in coal flames. Technical progress report, December 15, 1994--March 30, 1995

摘要

In this paper we present a methodology for measuring the elements of the Mueller (Scattering) matrix, which in turn can be used to determine the size of soot monomers and agglomerates in flames. The experimental system to be used is composed of two linear polarizers, two quarter wave plates and a half wave plate along with a light source (Nd:YAG Laser). The preliminary independent parameters in this setup are the polarizer angles (xi)(sub 1), (xi)(sub 2) and the retarder angles (beta)(sub 1), (beta)(sub 2) and (beta)(sub 3), which can be varied to obtain different condition numbers (CN). If the CN is large, then the Mueller matrix elements determined from experiments would not be reliable. However by using a proper set of (xi) and (beta) values, one can reduce the CN to be less than 10. This concept is discussed for different fractal-like soot agglomerates. It is shown that even if there is (+-)7.5% error in measured intensities, the recovered S(sub 11) and S(sub 12) elements are virtually identical to the true values. These S(sub ij) elements can be used in an inverse algorithm to identify the size of soot monomers and agglomerates.