Real‐Time Visualization of Internal and External Concentration Fields in Multiphase Systems via Laser‐induced Fluorescence and Rainbow Schlieren Deflectometry During and After Droplet Production

Abstract

Abstract The applicability of laser‐induced dye fluorescence (LIF) and rainbow schlieren deflectometry (RSD) for qualitative, non‐invasive real‐time visualization of spatial concentration distributions in two standard reference systems is presented. The combination of LIF and RSD enables measurements inside and outside of droplets and is able to overcome limitations of both measurement techniques. Experimental results in the presence of interfacial phenomena are compared and the connection between inner and outer effects is shown during droplet production at a capillary.