One-dimensional simulation of the breakup of capillary jets of conducting liquids. Application to EHD spraying

Nonlinear breakup of charged liquid jets is numerically analyzed in this wo rk in the limit of a very small electrical Strouhal number T-e/T-b much les s than 1 (i.e. negligible charge relaxation effects, applicable to highly c onducting liquids), where T-e is the electric relaxation time of charges, a nd T, is the breakup time in a Lagrangian framework following the liquid je t at its average axial velocity. The influence of the electrical Bond's num ber and viscosity on (i) the capillary Rayleigh's most probable breakup len gth, (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 st eady cone-jet mode, and its range of applicability to those particular prob lems discussed. Previous experimental results [Mutoh et al., 1979, Converge nce and disintegration of liquid jets induced by an electrostatic field. J. Appl. Phys. 50, 3174-3179; Clopeau and Prunet-Foch, 1989, Electrostatic sp raying 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 stabili ty of a steady Taylor cone-jet at atmospheric pressure. (C) 1999 Elsevier S cience Ltd. All rights reserved.