Liquid dielectric

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

Cooling of a Multichip Electronic Module by Means of Confined Two-Dimensional Jets of Dielectric Liquid

Abstract: Experiments were performed to investigate single-phase heat transfer froma smooth 12.7 {times} 12.7 mm{sup 2} simulated chip to a two-dimensional jet of dielectric Fluorinert FC-72 liquid issuing from a thin rectangular slot into a channel confined between the chip surface and nozzle plate. The effects of jet width, confined channel height, and impingement velocity have been examined. Channel height had a negligible effect ont eh theat transfer performance of the jet for the conditions of the present study. A correlation for the convective heat transfer coefficient is presented as a function of jet, width, heat length, flow velocity, and fluid properties. A self-contained multichip cooling module consisting of a 3 {times} 3 array of heat sources confirmed the uniformity and predictability of cooling for each of the nine chips, and proved the cooling module is well suited for packaging large arrays of high-power density chips.

Mechanical vs. electrical failure mechanisms in high voltage, high energy density multilayer ceramic capacitors

Abstract: Causes of breakdown, both mechanical and electrical, in high voltage, high energy density, BaTiO3 capacitors were studied. The flexural strength of the capacitors was 96 MPa. Failure was due to surface defects or pores close to the surfaces of the samples. The dielectric breakdown strength of the samples was 181 kV/cm. The causes of breakdown were either electrode end effects or pores between the dielectric and electrode layers. Weibull statistics were used to determine if there was a correlation between mechanical failure and dielectric breakdown. A strong correlation between the two types of failure was not found in the study, in contrast to earlier studies of single dielectric layer capacitor materials.

Ion Drag Pumping. II. Experiment

Abstract: The problem of the electrical pumping of a dielectric liquid along lines of the applied field is considered experimentally. The pressure generated by typical pumps are studied in detail, often in novel fashions; e.g., by varying the liquid flow velocity, the electrode spacing, or the liquid temperature while the applied field is held constant. It is shown that the experimental data are consistent with an ion emission model of the phenomenon, but that the emission is not necessarily space‐charge‐limited; photomicrographs are presented to show the effects of the emission process on the electrodes.

Electrophoresis of a charged droplet in a dielectric liquid for droplet actuation.

Abstract: Electrophoretic motion of a charged droplet in a dielectric fluid under an electric field has been investigated experimentally for use as a microdroplet actuation method. The effects of the droplet size, electric field strength, and electrolyte concentration and ion species on the charging of an aqueous droplet have been examined. The amount of electrical charging has been measured by two different methods: indirect measurement using the image analysis of droplet motion and direct measurement using the electrometer. Quantitative comparison of the droplet charge measured experimentally and the theoretical value of a perfectly conductive sphere shows that an aqueous droplet is less charged than the corresponding perfectly conductive sphere. The limiting effect on electrical charging is more significant for an electrolyte droplet, and the effect is positively correlated to the electrolyte concentration rather than the ion species. This implies that the low electrical conductivity of water is not a major cause of the limiting effect. The scaling law of the charging amount for a deionized water droplet nearly follows that of the perfect conductor, whereas for an electrolyte droplet, the scaling law exponent is slightly higher. Some advantages and potentials of the current droplet actuation method are also discussed in comparison with the conventional ones.

Recent progress in nanofluids based on transformer oil: preparation and electrical insulation properties

Abstract: Given the adoption of ultrahigh-voltage ac and dc power transmission, it is desirable to develop a new kind of oil-paper insulation system, with higher dielectric strength and smaller volume compared with conventional insulation systems, in order to reduce the volume and mass of high-voltage power transformers and improve their long-term operational reliability [1], [2]. Methods of improving the dielectric properties of the oil-paper insulation have therefore been widely investigated [3], [4]. The most influential factors affecting the performance of oil-paper insulation systems are the low dielectric strength of transformer oil and its degradation caused by water and other contaminants [5]. The dielectric strength of oil-paper insulation may be increased by filtering the oil in order to remove water and other contaminants [6]. However, further increase in the dielectric strength of the oil is required in order to achieve reduction of transformer volume and mass.