Image-Based System for Particle Counting and Sizing

A procedure is developed to provide measurements of particle size by adapting parts of a commercially available particle image velocimetry system to obtain in situ digital images of the particles. The procedure is nonintrusive and is able to capture images of the particles as they are mixed, thus avoiding the need for disturbing the flow or withdrawing samples for later analysis. Measured size distributions are shown to compare closely with manufacturer's values for standard polystyrene spherical particles, and particles with diameters as small as 6 μm are resolved. The system also is shown to track changes in particle-size distribution during an aggregation test. In addition, information on particle geometry is obtained, which should be useful for improving the ability to model aggregation processes. A simple modeling framework based on the Smoluchowski equation is presented to demonstrate the use of data obtained with this procedure in particle aggregation modeling.