Instantaneous imaging of particle size and spatial distribution in two-phase flows

A new optical diagnostic capable of instantaneously measuring the size and spatial distribution of many particles in two-phase flows of moderate number densities (10(3)-10(4)/cm(3)) is described. The method utilizes a broadband light source to illuminate a section of the flow field and two solid-state cameras to image the spatial distribution of the illuminated particles. Individual particle image intensities are related to particle size by comparison with Mie scattering calculations. Experimental results for monodisperse droplet streams are presented and are in good agreement with theory. Appropriate application regimes based on particle size, number density, and camera constraints are given.