Dynamics of drop formation in an electric field
- Purdue Univ., West Lafayette, IN (United States). School of Chemical Engineering
The effect of an electric field on the formation of a drop of an inviscid, perfectly conducting liquid from a capillary which protrudes from the top plate of a parallel-plate capacitor into a surrounding dynamically inactive, insulating gas is studied computationally. This free boundary problem which is comprised of the surface Bernoulli equation for the transient drop shape and the Laplace equation for the velocity potential inside the drop and the electrostatic potential outside the drop is solved by a method of lines incorporating the finite element method for spatial discretization. The finite element algorithm employed relies on judicious use of remeshing and element addition to a two-region adaptive mesh to accommodate large domain deformations, and allows the computations to proceed until the thickness of the neck connecting an about to form drop to the rest of the liquid in the capillary is less than 0.1% of the capillary radius. The accuracy of the computations is demonstrated by showing that in the absence of an electric field predictions made with the new algorithm are in excellent agreement with boundary integral calculations and experimental measurements on water drops. Computational predictions of the primary drop volume and drop length at breakup are reported over a wide range of values of the ratios of electrical gravitational, and inertial forces to surface tension force. When the magnitude of the step change in field strength is small, the results of the new transient calculations accord well with those of an earlier stability analysis and thereby provide yet another testament to the accuracy of the new algorithm.
- OSTI ID:
- 343716
- Journal Information:
- Journal of Colloid and Interface Science, Vol. 213, Issue 1; Other Information: PBD: 1 May 1999
- Country of Publication:
- United States
- Language:
- English
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