Liquid dielectric

About: Liquid dielectric is a research topic. Over the lifetime, 3702 publications have been published within this topic receiving 45150 citations.

Determination of electric field distribution in oil using the Kerr-effect technique after application of DC voltage

Abstract: A technique based on the Kerr electrooptic effect is used for the measurement of electric field strength in dielectric liquids such as transformer oil. An elliptically polarized laser beam is used as incident light and the applied DC voltage is modulated with an AC voltage. Using this technique, low-level electric fields are measured in liquids with small Kerr constants using a short electrode length. The change of electric field distribution with respect to time after application of a DC step voltage and the nonuniformity of the electric field in water-saturated transformer oil are also studied. The electric field in water-saturated transformer oil is shown to be distorted, and the charge density is shown to be about 1 nC/cm/sup 3/ when the applied step DC voltage is 2 kV. However, electric field distribution is found to be uniform in dry transformer oil, dry silicone oil, and water-saturated silicone oil. >

Deformation, breakup and motion of a perfect dielectric drop in a quadrupole electric field

Abstract: A detailed nonlinear analysis of the deformation and breakup of a perfect dielectric (PD) drop, suspended in another perfect dielectric fluid, in the presence of a quadrupole electric field is presented using analytical (asymptotic) and numerical (boundary integral) methods. The quadrupole field is the simplest kind of an axisymmetric non-uniform electric field. A drop, when placed at the center of such a field, does not translate, thus allowing systematic investigation of the effect of non-uniformity of the electric field. The deformation of a drop under a quadrupole field for PD-PD systems exhibits several novel features as compared to that of a drop under a uniform electric field. The first order analysis predicts oblate deformation for a PD-PD system when the dielectric constant of the suspending medium is larger than that of the drop (Q = ei/ee < 1). This is in sharp contrast to uniform electric fields where oblate shapes are observed only in leaky dielectric systems. Prolate shapes are observed for ...

Breakdown mechanism of liquid nitrogen viewed from area and volume effects

Abstract: We investigated the area and volume effects on the breakdown strength in liquid nitrogen (LN/sub 2/) to discuss the breakdown mechanism in cryogenic liquids for superconducting power apparatus. We measured breakdown voltages in LN/sub 2/ with and without thermal bubbles over a very wide range of the electrode size. Experimental results revealed that the breakdown mechanism changed from an area dominant to volume effective region at larger electrode configurations in LN/sub 2/. Moreover, we discussed the contribution rate of area and volume effects to the breakdown strength in LN/sub 2/. It was suggested that a mutual contribution of area and volume effects appeared in breakdown characteristics in LN/sub 2/ under thermal bubble conditions, as a phenomenon peculiar to cryogenic liquids. Consequently, we pointed out that it is very important to consider both thermal bubbles and electrode surface condition for HV insulation of superconducting power apparatus.

Investigation of effective interface potentials by electrowetting

Abstract: We study a situation where the complete wetting of a dielectric solid by a dielectric liquid, in a conducting surrounding, is altered by the application of an electrical potential difference. Calculations predict a dewetting transition towards pseudo-partial wetting. More generally, in a pseudo-partial wetting situation (pre-existing or electrically induced), the mesoscopic film coexisting with the macroscopic droplet is expected to be thinned by the electrostatic pressure in a way that is directly related to its effective interface potential. This points out a possibility to tune the thickness of a fluid film in a nanometric regime.