Abstract
In DoD inkjet printing, an ink jet is ejected from a nozzle, which forms a liquid filament after breaking up from the nozzle. The stability of this filament must be controlled for optimal print quality. This stability is the focus of the research comprised in this thesis.
We start the investigation by constructing a model, which accurately describes the dynamics of a liquid filament (chapter 2). For the model that describes the stability of the liquid filament, we apply 4 assumptions: a) The filament is an axially symmetric body of Newtonian fluid. b) The dynamics of the filament can be described in the slender jet approximation. c) The viscosity and the surface tension of the fluid are constant over time and space. d) We use the sharp interface approximation for the fluidair interface. The sharp interface approximation leads to a singularity at pinchoff. The pinchoff singularity is regularized using a modification of the surface tension. This modification conserves mass and momentum. With this regularization, the model can simulate jet breakup beyond the pinchoff.
The presented numerical model is validated by analytical, experimental and numerical results of the RayleighPlateau instability in chapter 2. In chapter 3 and 4 the contraction and stability of the liquid filament are studied. In chapter 5 an experimental method to measure the ink velocity inside the filament optically is presented. This experimental method is validated using the numerical model presented in chapter 2. Finally in chapter 6, we demonstrate how to obtain a stream of widelyspaced droplets by imposing a superposition of two RayleighPlateau instabilities. The growth of the perturbations and the resulting drop formation are studied with linear theory and a fully nonlinear model, resulting in a deep insight in the jet breakup.
Original language  English 

Awarding Institution 

Supervisors/Advisors 

Award date  20 Dec 2013 
Place of Publication  Enschede 
Publisher  
Print ISBNs  9789036535786 
DOIs  
Publication status  Published  20 Dec 2013 
Keywords
 IR88236
 METIS299629
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Driessen, T. W. (2013). Drop formation from axisymmetric fluid jets. Enschede: Universiteit Twente. https://doi.org/10.3990/1.9789036535786