scholarly journals Numerical Analysis of Fluid Flows within and around Water Drops Translating in the Oil Phase in a Uniform Electric Field

2003 ◽  
Vol 46 (5) ◽  
pp. 295-300
Author(s):  
Morito MARUYAMA ◽  
Ryoji NAKATA ◽  
Manabu YAMAGUCHI
Keyword(s):  
Numerical Analysis ◽  
Electric Field ◽  
Fluid Flows ◽  
Uniform Electric Field ◽  
Water Drops ◽  
Analysis Of Fluid Flows

The vibration of electrified water drops

1971 ◽  
Vol 322 (1551) ◽  
pp. 523-534 ◽  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Axial Ratio ◽  
Uniform Electric Field ◽  
Interferometric Technique ◽  
Photographic Analysis ◽  
Wide Range ◽  
Water Drops ◽  
Strength And Deformation ◽  
A Charge

Pressure has been used as the principal parameter in calculations of the fundamental vibrational frequencies of spherical drops of radius R , density ρ, and surface tension T carrying a charge Q or uncharged spheroidal drops of axial ratio a / b situated in a uniform electric field of strength E . Freely vibrating charged drops have a frequency f = f 0 ( 1 - Q 2 /16π R 3 T ) ½ , as shown previously by Rayleigh (1882) using energy considerations; f 0 is the vibrational frequency of non-electrified drops (Rayleigh 1879). The fundamental frequency of an uncharged drop in an electric field will decrease with increasing field strength and deformation a / b and will equal zero when E ( R )/ T ) ½ = 1.625 and a / b = 1.86; these critical values correspond to the disintegration conditions derived by Taylor (1964). An interferometric technique involving a laser confirmed the accuracy of the calculations concerned with charged drops. The vibration of water drops of radius around 2 mm was studied over a wide range of temperatures as they fell through electric fields either by suspending them in a vertical wind tunnel or allowing them to fall between a pair of vertical electrodes. Photographic analysis of the vibrations revealed good agreement between theory and experiment over the entire range of conditions studied even though the larger drops were not accurately spheroidal and the amplitude of the vibrations was large.

Breakup of a conducting drop in a uniform electric field

2014 ◽  
Vol 754 ◽  
pp. 550-589 ◽  
Author(s):  
Rahul B. Karyappa ◽  
Shivraj D. Deshmukh ◽  
Rochish M. Thaokar
Keyword(s):  
Steady State ◽  
Numerical Analysis ◽  
Electric Field ◽  
Viscosity Ratio ◽  
Uniform Electric Field ◽  
Shape Prior ◽  
Capillary Stress ◽  
Electric Stress ◽  
Dc Electric Field ◽  
Axisymmetric Shape

AbstractA conducting drop suspended in a viscous dielectric and subjected to a uniform DC electric field deforms to a steady-state shape when the electric stress and the viscous stress balance. Beyond a critical electric capillary number $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}\mathit{Ca}$, which is the ratio of the electric to the capillary stress, a drop undergoes breakup. Although the steady-state deformation is independent of the viscosity ratio $\lambda $ of the drop and the medium phase, the breakup itself is dependent upon $\lambda $ and $\mathit{Ca}$. We perform a detailed experimental and numerical analysis of the axisymmetric shape prior to breakup (ASPB), which explains that there are three different kinds of ASPB modes: the formation of lobes, pointed ends and non-pointed ends. The axisymmetric shapes undergo transformation into the non-axisymmetric shape at breakup (NASB) before disintegrating. It is found that the lobes, pointed ends and non-pointed ends observed in ASPB give way to NASB modes of charged lobes disintegration, regular jets (which can undergo a whipping instability) and open jets, respectively. A detailed experimental and numerical analysis of the ASPB modes is conducted that explains the origin of the experimentally observed NASB modes. Several interesting features are reported for each of the three axisymmetric and non-axisymmetric modes when a drop undergoes breakup.

Numerical Analysis of the Effect of Non Uniform Electric Field on the Trajectory of Micro Water Jet

2015 ◽  
Author(s):  
Satyabrata Mohanty ◽  
Kornel F. Ehmann ◽  
Jian Cao
Keyword(s):  
Numerical Analysis ◽  
Electric Field ◽  
Jet Impingement ◽  
Water Jet ◽  
Uniform Electric Field ◽  
Static Electric Field ◽  
Liquid Dielectrophoresis ◽  
Fine Control ◽  
Unique Approach ◽  
And Control

In spite of its inherent advantages as a manufacturing tool, water-jet has not been extensively applied to the field of micro-manufacturing due to its low tolerance and poor control of the position of jet impingement. This paper explores the possibility of using the phenomenon of liquid dielectrophoresis to deflect and control the trajectory of a water jet in air. An approach is suggested using a localized non-uniform static electric field over a micro water jet with diameters in the range of 25–100 micrometers. The water jet has been modelled as a thin dielectric column and the numerical analysis of the electric field distribution has been carried out using COMSOL to analyze the generated forces and predict the scale of deflection of the jet. This unique approach of harnessing the polar nature of water using the phenomenon of dielectrophoresis might be useful in achieving fine control of the water jet’s trajectory especially in micro water jet material processing.

scholarly journals Study of the Behavior of Water Droplets Under the Influence of a Uniform Electric Field on Conventional Polyethylene and on Crosslinked Polyethylene (XLPE) with MgO Nanoparticles Samples

2017 ◽  
Vol 7 (1) ◽  
pp. 1323-1328 ◽  
Author(s):  
C. Charalambous ◽  
M. Danikas ◽  
Y. Yin ◽  
N. Vordos ◽  
J. W. Nolan ◽  
...  
Keyword(s):  
Electric Field ◽  
Uniform Electric Field ◽  
Water Droplets ◽  
Nano Structure ◽  
Insulating Materials ◽  
Mgo Nanoparticles ◽  
Underground Cables ◽  
Flashover Voltage ◽  
Surface Damages ◽  
Water Drops

It is well known that polyethylene (PE) and cross-linked polyethylene (XLPE) are suitable insulating materials for underground cables. Samples of PE and of XLPE with MgO nanoparticles were investigated regarding their flashover behaviour with a uniform electric field and water droplets of various conductivities. In the present paper, the effect of the mounting arrangement of the water drops on the value of the flashover voltage and the effect of the volume of dripping water on the flashover voltage were also studied. Surface damages were analyzed using Scanning Electron Microscopy (SEM) studies and the study of the nano-structure of the samples was studied using the SAXS system.

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