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Liquid dielectric
About: Liquid dielectric is a research topic. Over the lifetime, 3702 publications have been published within this topic receiving 45150 citations.
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TL;DR: In this article, the authors used a unified lattice Boltzmann method to calculate the Coulomb force induced by the electric field exerting on free charges injected from the inner cylinder.
16 citations
TL;DR: In this article, the deformation of a water meniscus at the end of a capillary tube through the action of electric forces is exploited to accelerate the ejection of a small uncharged droplet.
Abstract: The paper presents recent improvements and results on the on-demand injection of small electrically neutral water drops in oil by high electric field pulses. The technique consists in applying a voltage pulse promoting the deformation of a water meniscus at the end of a capillary tube through the action of electric forces. For pulses of calibrated energy, the transient deformation can lead to the inertia-based ejection of a small uncharged droplet. Application of in-house developed multi-stage electric pulses offers, in contrast to usual single pulses, wider ranges of droplet size, improved reproducibility and stable ejection trajectories. Influence of the main parameters on the extracted droplet diameter is presented: it is shown that, by using capillary tubes of outer tip diameter close to 0.5 mm, it is possible to obtain, in a reproducible way, drops of diameter ranging from less than 15 μm up to more than 250 μm.
16 citations
TL;DR: In this paper, the dynamics of an electrical discharge-generated vapour bubble between the tool and the workpiece after its splitting are investigated by using the boundary integral equation method, and the development of a liquid jet on the boundary of the each of the upper and lower parts of the bubble and the impingement of the liquid jets on the nearby rigid surfaces are sought.
Abstract: Electrical discharge machining (EDM) is a powerful technique for machining of hard and brittle materials. In this process, because of electrical discharge, a vapour bubble is generated in the dielectric liquid between the tool and the workpiece. The growth and collapse phases of the vapour bubble have significant effect on the hydrodynamic behaviour of the dielectric liquid domain between the tool and the workpiece and cause molten material to escape from the crater. Previous numerical studies on the dynamics of an electrical discharge-generated vapour bubble have simulated the growth and collapse of the bubble until it has taken the shape of an hour-glass. This is necking phenomenon which is followed by splitting of the bubble into two parts. In this paper dynamics of an electrical discharge-generated vapour bubble between the tool and the workpiece after its splitting are investigated by using the boundary integral equation method. Development of a liquid jet on the boundary of the each of the upper and lower parts of the bubble and the impingement of the liquid jets on the nearby rigid surfaces are sought. This paper consists of two parts. In part one, the vapour bubble is initially located between the tool and the workpiece. Consequently the dynamic behaviour of the two parts of the bubble in the absence of the buoyancy forces are symmetric with respect to a horizontal axis through the mid-point between the tool and the workpiece. In part two, the elrecrical discharge-generated vapour bubble is initially located in the vicinity of the workpiece. Therefore during the necking phenomenon the upper part of the bubble is smaller than its lower part. Consequently the dynamic behaviour of the two parts of the bubble after its splitting are significantly different.
16 citations
Patent•
04 Aug 2012
TL;DR: Hard disk drives and computing systems to which they are connected are cooled by submerging the computing systems into a dielectric liquid coolant in a tank and by thermally coupling the hard disk drives to a heat conductive extension that is partly submerged into the coolant and partly out of the coolent as discussed by the authors.
Abstract: Hard disk drives and computing systems to which they are connected are cooled by submerging the computing systems into a dielectric liquid coolant in a tank and by thermally coupling the hard disk drives to a heat conductive extension that is partly submerged into the coolant and partly out of the coolant. To keep the hard disks drives out of the coolant, they are mounted to the part of the heat conductive extension that is out of the coolant. In such a configuration, the hard disk drives are cooled through conduction of the heat from the hard disk drive to the coolant via the heat conductive extension. A pump may be used to move warmer coolant from the tank into a heat exchanger where the coolant is cooled and to move the cooled coolant back into the tank.
16 citations
26 Jul 2009
TL;DR: Natural ester seed oil based dielectric fluid is an environmentally advantaged fluid that is increasingly being used as a replacement for mineral oil and for high temperature flashpoint liquids, including silicone and R-TEMP as discussed by the authors.
Abstract: Natural ester seed oil based dielectric fluid is an environmentally advantaged fluid that is increasingly being used as a replacement for mineral oil and for high temperature flashpoint liquids, including silicone and R-TEMP. This report updates experience with use of the fluid over the last two years. Considerable studies have been conducted to investigate heat aging performance of cellulose, electrical contact thermal stability, dielectric strength, moisture sensitivity, and cold temperature performance. A series of reports presents a summary of work that has been completed to date and examines customer experience with the use of Natural Esters in real transformers. The work contains both new transformers and retro-fills in Distribution and Power Transformers as well as Step Voltage Regulators and Switchgear.
16 citations