ONE-DIMENSIONAL SIMULATION OF THE BREAKUP OF CAPILLARY JETS OF CONDUCTING LIQUIDS. APPLICATION TO E.H.D. SPRAYING

Abstract

Nonlinear breakup of charged liquid jets is numerically analyzed in this work in the limit of a very small electrical Strouhal number T e/ T b≪1 (i.e. negligible charge relaxation effects, applicable to highly conducting liquids), where T e is the electric relaxation time of charges, and T b is the breakup time in a Lagrangian framework following the liquid jet at its average axial velocity. The influence of the electrical Bond’s number and viscosity on (i) the capillary Rayleigh’s most probable breakup length, (ii) the breakup time, (iii) the volume of the satellite, and (iv) the charge of both main drop and satellite, are analyzed. The model is related to the microjet break-up phenomena in the electrospraying of liquids in steady cone-jet mode, and its range of applicability to those particular problems discussed. Previous experimental results [Mutoh et al., 1979, Convergence and disintegration of liquid jets induced by an electrostatic field. J. Appl. Phys. 50, 3174–3179; Clopeau and Prunet-Foch, 1989, Electrostatic spraying of liquids in cone-jet mode. J. Electrostatics 22, 135–159.] support our numerical finding that the influence of the electrical Bond’s number on Rayleigh’s length is small within the usual parametrical limits of stability of a steady Taylor cone-jet at atmospheric pressure.