Effect of polymers on the suppression of satellite droplets during the jet breakup in inkjet printing

In inkjet printing, high speed liquid jets break up into droplets due to a capillary instability. This instability often leads to the formation of secondary satellite droplets that deteriorate the quality of a print. In this work, we study the jet formation and the breakup process using Direct Numerical Simulations (DNS). In particular, we investigate the effect of polymer additives in suppressing the formation of satellite drops. Our results show that the addition of small concentrations of polymers can lead to the suppression of satellite droplets. However, if the polymer concentration increases beyond a certain limit, the jet breakup is impeded altogether. Similar phenomenology was observed in the experimental study of Sen et al. [1]. We further analyze the flow inside the jet during breakup and examine the relative contribution of the polymeric stresses, the viscous stresses and the surface-tension force, to the jet formation and breakup processes.

[1] Sen, U., Datt, C., Segers, T., Wijshoff, H., Snoeijer, J. H., Versluis, M., & Lohse, D. (2021). The retraction of jetted slender viscoelastic liquid filaments. Journal of fluid mechanics, 929, A25.