Pulsating electrohydrodynamic cone-jets: From choked jet to oscillating cone

Pulsating cone-jets occur in a variety of electrostatic spraying and printing systems. This paper reports an experimental study of the pulsation frequency to reconcile two models based on a choked jet and an oscillating cone, respectively. The two regimes are demarcated by the ratio of the supplied flow rate (Qs) to the minimum flow rate (Qm) required for a steady Taylor cone-jet. When Qs ≈ Qm, the electrohydrodynamic flow is choked at the nozzle because the intermittent jet, when on, emits mass at the minimum flow rate; the pulsation frequency in the choked jet regime is proportional to Qs/Qm. When Q s ≈ Qm, the Taylor cone anchored at the nozzle experiences a capillary oscillation analogous to the Rayleigh mode of a free drop; the pulsation frequency in the oscillating cone regime plateaus to the capillary oscillation frequency, which is independent of Qs/Q m. © 2011 Cambridge University Press.

Duke Scholars

Author Chuan-Hua Chen Thomas Lord Department of Mechanical Engineering and Materia ...