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Special Topics & Reviews in Porous Media: An International Journal
ESCI SJR: 0.259 SNIP: 0.466 CiteScore™: 0.83

ISSN Druckformat: 2151-4798
ISSN Online: 2151-562X

Special Topics & Reviews in Porous Media: An International Journal

DOI: 10.1615/SpecialTopicsRevPorousMedia.2018022333
pages 329-345

ELECTROHYDRODYNAMIC INSTABILITIES OF ATOMIZATION AND RAYLEIGH REGIMES FOR A DIELECTRIC LIQUID JET EMANATED WITH PARABOLIC VELOCITY PROFILE INTO A STATIONARY DIELECTRIC GAS THROUGH POROUS MEDIUM

Mohamed F. El-Sayed
Department of Mathematics, Faculty of Education, Ain Shams University, Heliopolis (Roxy), Cairo, Egypt; Department of Mathematics, College of Science, Qassim University, P. O. Box 6644, Buraidah 51452, Saudi Arabia

ABSTRAKT

A linear electrohydrodynamic (EHD) axisymmetric analysis is performed analytically to arrive at the dispersion relation that governs the instability of a dielectric liquid jet emanated with parabolic velocity profile into a dielectric gas through porous medium. The velocity profile within the liquid jet is varied from parabolic to uniform in order to model the effects on its relaxation on the liquid jet instability and intact length under the effects of electric field and porous medium. Both the atomization and Rayleigh regimes of instability have been discussed for all parameters included. The results indicate that the closer the velocity profile to uniform the most pronounced the instability, and both the electric field and porosity of porous medium have stabilizing effects, while increasing gas to liquid density ratio, medium permeability and dielectric constants promote instability in the two regimes. The Weber number, in the atomization regime, has a destabilizing effect, while it has a stabilizing effect in the Rayleigh regime. The kinematic viscosities are found to have dual roles on the stability of the system in both regimes separated by a critical wave number in each case. Finally, we conclude that the system in the atomization regime is more unstable than in the Rayleigh regime, and also the system in the presence of electric field and porous medium is more unstable than in their absence.