Computational and theoretical analysis of ink-jets drop formation and breakup
Abstract
The dynamics of drop formation from a nozzle as well as drop oscillations in air find applications in industrially important processes including inkjet printing, surface property measurement, atomization and DNA microarraying. Three important aspects of these problems are considered in this dissertation. The first regards the formation and breakup of primary drops from a capillary with a constant or oscillatory flow rate and the dynamics of recoiling and breakup of the accompanying satellite drops. The second concerns the surfactant effects on the dynamics of recoiling and breakup of satellite drops and drop oscillations. The third is related to the scaling theory for the breakup of a liquid jet in the presence of insoluble surfactant. In this dissertation, highly accurate and rigorous numerical algorithms based on the Galerkin finite element method (G/FEM) are developed for the prediction of: (1) the formation and breakup of liquid drops from capillaries with constant or oscillatory flow rate, (2) the recoiling dynamics of satellite drops with or without insoluble surfactant, and (3) the nonlinear oscillations of viscous drops in air. To support the computational analysis, experimental observations of drop formation are made using high speed digital imaging. Theories are developed to improve fundamental understanding of the physics underlying these free surface flow problems. One of the most significant results reported is the discovery of two new scaling regimes with distinct dynamics for the breakup of a filament in the presence of insoluble surfactant. Another significant result is the development of a new approach to forming drop-on-demand (DOD) drops whose radii are much smaller than those of nozzles that produce them.
Degree
Ph.D.
Advisors
Basaran, Purdue University.
Subject Area
Chemical engineering
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