Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
724802 | Journal of Electrostatics | 2006 | 6 Pages |
The behaviour of three high viscosity (4875, 12 125 and 58 560 mPa s), dielectric liquids was investigated at flow rates of 10−10, 10−12 and 10−14 m3 s−1 and the applied voltage range 6–15 kV. In these experiments, due to the low electrical conductivity of the liquids (10−13 S m−1) and therefore the ensuing high electrical relaxation time, classical electrohydrodynamic atomization conditions are not satisfied. Only dripping and unstable jetting were observed at 4875 mPa s. A transition from no jetting to stable microthreading was observed for the 12 125 and 58 560 mPa s samples. The relics accompanying the transition were found to change from discrete droplets to a continuous filament. Stable microthreading, which generates uniform filaments, was obtained for the 12 125 mPa s sample at flow rates 10−10 and 10−12 m3 s−1 and in the case of the 58 560 mPa s sample at all the flow rates investigated. The high viscosity assisted stable microthreading with the filament diameter decreasing with increasing applied voltage and more dramatically decreasing with reducing flow rate.