In situ particle size measurements using a two-color laser scattering technique

A technique using light scattered from individual particles in the near-forward direction has been developed to measure particle size in the range of 10-200 microns. This technique uses the Mie scattering theory to relate the measured light intensity to particle size based on calibration techniques employing pinholes and water droplets of known size. A unique two-color optical arrangement is used to minimize the edge effect, which can cause incorrect size measurements for particles that pass through the edge of the laser beam focal volume. In this paper, the experimental technique and the results of size measurements obtained with this technique for water droplets and pulverized coal particles are presented.