An experimental investigation into liquid jetting modes and break-up mechanisms conducted in a new reduced gravity facility

Abstract

Liquid jets, important to many industrial applications including various drop-on-demand processes, are experimentally produced in reduced gravity conditions and analysed to determine the mode the liquid jet is operating in. Three physically different modes of liquid jetting are observed along with their associated break up mechanisms and discussed. Additionally, a) the theoretical transition between jetting and the onset of chaotic dripping is shown to be valid over a range of Re and We numbers in a reduced gravity environment; b) the theoretical transition between a convective and an absolute instability acting on a liquid jet does not appear valid for high Reynolds number jets operating in reduced gravity; c) for the first time, chaotic dripping has been observed and documented in reduced gravity; and, d) a transition is shown to exist in reduced gravity between chaotic dripping and quasi-steady growth. The work has applications to systems operating in both reduced gravity and in select systems operating in normal gravity. The work has been highly successful and has demonstrated the utility of the new Australian test facility in providing adequate test time and reduced gravity conditions to study sensitive phenomena under reduced gravity conditions.