Optical Sizing of Droplets and Particals

Instrumentation for optical sizing of droplets and particles is currently widely used for research and industrial development. The seminar will explain measurement requirements and the physical insight that they can provide. The principle of operation of current optical techniques, including Laser Diffraction (Malvern Particle Analyser), Phase Doppler anemometer and amplitude based particle sizing will be reviewed, and the advantages and disadvantages of the techniques will be summarised and sources of erroneous sizing measurements will be explained using light scattering calculations and experimental results. The shadow Doppler velocimeter, a new instrument for simultaneous measurement of particle shape, size and velocity will be presented. This is currently the only instrument that can obtain measurements in applications involving particles with random shape, for example powder production in the chemical industry, coal combustion, paint sprayin