Numerical Analysis of Viscosity and Surface Tension on Microdroplet Dynamics in Microelectromechanical Systems Applications

Microelectromechanical systems (MEMS) have instigated transformative advancements, notably in controlled microdroplet generation, offering applications across diverse industrial sectors. Precise control of fluid quantities at microscales has emerged as pivotal for myriad fields, from microfluidics to biomedical engineering. In this investigation, the impacts of fluid viscosity and surface tension on microdroplet formation were meticulously studied. For this purpose, a microdispenser, actuated piezoelectrically and fitted with an 18-micrometer diameter nozzle, was employed. This setup facilitated precise fluid manipulation, enabling a systematic study of fluid behavior during droplet creation. Three fluids, specifically water, ink, and ethanol, were examined to decipher the influences of their inherent properties on microdroplet generation. Emphasis was laid on both primary and satellite droplets due to their direct implications in industrial applications. Observations revealed that fluids with elevated surface tension and diminished viscosity yielded larger microdroplets. Conversely, fluids manifesting greater surface tension underwent rapid breakup upon ejection, culminating in the genesis of several diminutive droplets. Such findings underscore the intricate relationship between fluid properties and droplet formation dynamics. This newly acquired understanding holds the potential to guide MEMS device design, ensuring the desired droplet size and distribution. Furthermore, these insights are poised to facilitate optimal microdispenser design and judicious fluid selection for applications spanning inkjet printing, microreactors, and drug delivery mechanisms.