Determination of particle size distribution by polarization analysis of the scattered light.

Fast online acquisition of particle size distribution has become a significant technique for both laboratory research and industrial application. In this paper, a particle sizing method based on the analysis of scatted light through image processing is proposed. Polarization ratio, which is defined by the ratio of the scattered intensity component polarized perpendicular to that polarized parallel, is induced to quantify the polarization status which, according to Mie scattering theory, is dependent on the particle diameter under a certain operating condition when the refractive index of the particle is known. Test rig is set up to realize the simultaneous acquisition of particle images polarized both perpendicular and parallel on CCD camera. Through image processing, the polarization ratio of the scattered light is obtained, based on which inverse calculation is performed according to Mie theory. The presented method is then applied to the size distribution determination of polystyrene particles suspending in water. The results obtained from experiments are compared with the calibrated values which renders a deviation less than 10%. The optical setup is also applied to the sizing of water droplets generated by an atomizer, which provides reasonable size distributions under different operating conditions in line with the reference values provided by the fabricator. [ABSTRACT FROM AUTHOR]