Drop-on-Demand: A Scale Analysis

An increasing number of applications deal with dispensing of micro-droplets. For several years the fluids used were mostly Newtonian with low viscosity but there is nowadays a tendency to use more complex fluids. Some recent applications are encountered in the pharmaceutical industry where there is a need of producing on-demand identical droplets of a given size that can be used for drug delivery and in bioengineering where droplets have to contain cells used for tissue manufacturing or organ printing. The objective of the paper is to show that scale analysis is an efficient tool to classify the physical phenomena contributing to the breakup of a jet or of a liquid filament of a complex fluid and to provide guidelines for controlling the droplet formation process.Copyright © 2013 by ASME