Experimental Characterization of Aerosol Flows Through Micro-Capillaries

Abstract

Understanding the forces which dictate fluid particle interaction is of high interest in the field of aerosol jet Direct Write (DW). Several methods utilizing shadowgraphy and Mie scattering were used to visualize particle flow exiting micro-capillaries. Experiments were designed such that results would offer insight into the effects of Stokes and Saffman force on particle trajectories. Comparison to these results allowed for the development of a theoretical model which was validated and used to optimize nozzle geometries for particle focusing. Optimized nozzle geometries resulted in the conclusion that under certain conditions Saffman force is applicable given an appropriate correction factor. Experimental results showed the successful collimation of aerosol particles into beams with widths as small as the particles diameter. Additionally, a Small Particle Sizing Algorithm (SPSA) utilizing standard shadowgraphy techniques was developed allowing for the simultaneous sizing and positioning of particles ranging from 3-10 µm in diameter.