INSITU LIGHT-SCATTERING DISSYMMETRY MEASUREMENTS OF THE EVOLUTION OF THE AEROSOL SIZE DISTRIBUTION IN FLAMES

A light scattering system using angular dissymmetry is used to map out the evolution of the size distribution of a nonabsorbing aerosol in a controlled methane-air flat flame. Silicon tetrachloride vapor is generated by bubbling argon through a pool of silicon tetrachloride (SiCl4) liquid and fed in controlled amounts into the flame, wherein silica (SiO2) particles are formed by oxidation of the SiCl4 vapor. A fractal analysis of light scattering data indicates that the particles are close to spherical. The scattered light intensity data at three different angular positions is inverted using the Mie light scattering expressions to determine the effective spherical aerosol size distribution assuming that the distribution can be described by a lognormal function. The results are compared to monodisperse inversion techniques and the predictions of a 1-D lognormal model. © 1992.