Print: | ISSN 0256-1115 |
Online: | ISSN 1975-7220 |
Korean Journal of Chemical Engineering,
Vol.33, No.3, 775-781, 2016 New criteria for filament breakup in droplet-on-demand inkjet printing using volume of fluid (VOF) method
A volume of fluid (VOF) numerical study is presented in which new pi number-based criteria are discussed that identify and separate three different regimes for a droplet-on-demand (DOD) print-head system. A trailing filament coalesces into the main droplet while the filament breaks into one or multiple satellite droplet(s). The numerical simulation results are compared with published large-scale experimental results that used a 2 mm diameter inkjet nozzle head, roughly 50 times larger than the actual diameter of inkjet outlets. Liquid filament break-up behavior is predicted using a combination of two pi-numbers, including either Weber (We)-Ohnesorge (Oh) number couplets or Reynolds (Re)-Weber (We) number couplets that are dependent only on the ejected liquid properties and the velocity waveform at the print-head inlet. These new criteria have merit over the currently existing ones that require accurate measurements of actual droplets to determine filament physical features like length and diameter [1].
Keywords:
Inkjet Printing; Droplet on Demand; Scale Modelling; Volume of Fluid (VOF); Filament Breakup
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