Furlani E.P.
Eastman Kodak Company, US
Keywords: ink jet printing, ink-jet, jet breakup, jet instability, jet modulation, slender jet analysis
Liquid microjets are inherently unstable and can be modulated in a controlled fashion to create steady streams of picoliter-sized droplets at frequency rates in the hundreds of kilohertz. Such modulation has been achieved using CMOS/MEMS technology, which enables low-cost high-throughput droplet generators for applications that range from printed electronics to high-speed inkjet printing. The design of microfluidic printing devices requires rigorous and time-consuming CFD analysis. In this presentation we discuss a method for performing rapid parametric analysis of droplet generation that is useful for the design of such devices. We present a model for predicting the nonlinear deformation and breakup of modulated slender microjets. We adopt a one-dimensional slender-jet approximation and model the behavior of the jet using a system of coupled thermal/fluidic PDEs. We use the method of lines to reduce the PDEs to a system of ODEs, and solve for the free-surface, velocity, and temperature along the jet. We present parametric studies of jet breakup as a function of modulation amplitude and wavelength, and discuss how these parameters influence the time-to-breakup, the size of filaments, and the structure of the free surface at pinch-off. We also present a fabricated CMOS/MEMS inkjet printhead and describe its underlying device physics.
Journal: TechConnect Briefs
Volume: 3, Technical Proceedings of the 2007 NSTI Nanotechnology Conference and Trade Show, Volume 3
Published: May 20, 2007
Pages: 444 - 447
Industry sector: Sensors, MEMS, Electronics
Topic: Micro & Bio Fluidics, Lab-on-Chip
ISBN: 1-4200-6184-4