Global Rainbow Refractometry with a Selective Imaging Method

摘要

Originally developed to measure the refractive index,global rainbow refractometry also permits the extraction of a size distribution.When this technique is applied to a spray with a large number of non-spherical particles,the number of small particles tends to be overestimated.A new approach in data acquisition is presented to solve this problem at least partially,resulting in a global rainbow of mainly spherical particles.Thus,measurement errors due to non-sphericity can be minimized.The global rainbow is constructed from an image series of rainbows of individual droplets,where images of the most spherical droplets are selected by use of certain criteria derived from computations of rainbows of single spheres using the Lorenz-Mie theory.