Conduction and Breakdown in Dielectric Liquids

Zahn, M.

doi:10.1002/047134608x.w2808

Cited by 3 publications

(8 citation statements)

References 28 publications

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“…An analysis of the results of works [50][51][52]55], devoted to the formation of near-electrode layers with enhanced conductivity, allowed the author of this review to substantiate in 1990 the possibility of concentrating the cations and anions located in near-electrode layers of water by passing a direct current with a density of up to several mA/cm 2 through the water. The ions released by the electrodes into the liquid and the H + and OHions resulting from a continuous dissociation of water molecules were considered as charge carriers supplied to the near-electrode regions.…”

Section: Formation Of Near-electrode Layers By Passing a Direct Currementioning

confidence: 99%

“…It was impossible to unambiguously calculate the field strength near the gap's center in water using the amplitude of the applied voltage and length d. The breakdown field strengths E b in the gap were therefore determined using the Kerr electrooptic effect in water, and by measuring the gradients of the refractive index using the Toepler method with a cylindrical lens (these techniques and equipment are described in [50,51] and the references therein).…”

Section: Changes In the Near-electrode Conditionsmentioning

confidence: 99%

“…Papers [51,52] and the references therein present the results from studies of the influence of electrode materials on the injection of charge carriers from electrodes into purified water, depending on the duration of the potential difference applied between the electrodes. Stainless steel, aluminum, brass, and copper served as the electrode materials.…”

Section: Injection Of Charges From the Electrode Materials Into Watermentioning

confidence: 99%

“…It was not explained in [51,52] in what facilities it is necessary to maintain a high voltage for ~1 ms using water insulation. This is probably associated with the search for ways of charging storage units from electromechanical generators and inductive storages.…”

Section: Injection Of Charges From the Electrode Materials Into Watermentioning

confidence: 99%

“…The ions released by the electrodes into the liquid and the H + and OHions resulting from a continuous dissociation of water molecules were considered as charge carriers supplied to the near-electrode regions. A combination of the charge carrier accumulation and concentration values experimentally determined in [51,52] was taken as the basis for an approximate selection of the direct-current parameters: for ρ ≈ 50 MΩ cm and E w 1 00 kV/cm, the required time was t w ~ 1 ms. It follows from here that, at a multiply lower field E Ò and a substantially longer duration of current flow t Ò with allowance for the lower mobility of ions and a possible partial recombination of charges, a criterion for the creation of near-electrode layers is the inequality E c t c ≥ E w t w = 10 5 V/cm × 10 -3 Ò = 10 2 V s/cm.…”

Section: Formation Of Near-electrode Layers By Passing a Direct Currementioning

confidence: 99%

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Water as an insulator in pulsed facilities (Review)

Gerasimov

2005

Instrum Exp Tech

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Transmission lines with distributed parameters are often used as electrical energy storage units and high-voltage (high-current) pulse shapers in electrophysical facilities. To increase the pulse power and reduce the dimensions of the equipment, deionized water, purified from mechanical impurities and gas, is used as an insulator in lines. Water has a high breakdown strength ((BS) ~ 130 kV/cm) at pulses with a duration of ~1 µ s and electrode areas of up to tens of square meters, a large value of the relative permittivity (~80), and a small loss tangent in the frequency range 0-1 GHz. Water also possesses a number of characteristics needed to achieve the above aims. We review here the data on the electrical properties of water and the studies of it published over the last three decades; the methods for increasing the water BS and the influence of numerous factors on the BS; the physical mechanism of water breakdown and the basic regularities of the BS in strong electric fields; the BS in the most frequently used electrode systems; formulas for calculating the water BS under different conditions and over the surfaces of solid dielectrics; the characteristics of mixtures of water and ethylene glycol or methanol; water purification systems for electrophysical facilities; the comparative parameters of coaxial energy storage units having various insulators, etc. The summary generalizes the brief and predominantly reference information on the electrical properties of water and its applications for researchers, engineers, and the users of the equipment having water insulation; it can help to solve related problems more quickly and reliably.

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Section: Formation Of Near-electrode Layers By Passing a Direct Currementioning

confidence: 99%

Section: Changes In the Near-electrode Conditionsmentioning

confidence: 99%

Section: Injection Of Charges From the Electrode Materials Into Watermentioning

confidence: 99%

Section: Injection Of Charges From the Electrode Materials Into Watermentioning

confidence: 99%

Section: Formation Of Near-electrode Layers By Passing a Direct Currementioning

confidence: 99%

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Water as an insulator in pulsed facilities (Review)

Gerasimov

2005

Instrum Exp Tech

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Liquid resistivity of pharmaceutical propellants using novel resistivity cell

Ahmad,

Rasekh,

Manivannan

et al. 2023

Sci Rep

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Metered-dose inhalers employ propellants to produce pharmaceutical aerosols for treating respiratory conditions like asthma. In the liquid phase, the DC volume resistivity of pharmaceutical propellants, including R134a, R152a, and R227ea, was studied at saturation pressures and room temperature (not vapour phase). These measurements are essential for industries like refrigerants. Aerosols from metered dose inhalers (MDIs) with these propellants become electrically charged, affecting medicament deposition in lung. The resistivity was measured using a novel concentric cylinder-type capacitance cell designed in-house. The resistivity for the propellants (R134a, R152a, and R227ea) was found to be 3.02 × 1010 Ωm, 2.37 × 109 Ωm and 1.31 × 1010 Ωm, respectively. The electrical resistivity data obtained was found to be at least two orders of magnitude higher than the limited data available in the literature. Challenges in the resistivity cell’s development and performance are discussed, with a focus on various propellants and their mixtures with ethanol and moisture concentrations. The resistivity of propellant mixtures containing moisture concentrations ranging from 5 to 500 ppm and ethanol concentrations ranging between 1000 and 125,000 ppm was determined. The resistivity was tested across 10-min and 1-h periods and was performed in accordance with the contemporary IEC 60247 standard.

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