Effect of temperature on flow electrification under dc electrical field

Gao, Youhui; Liu, Feng; Lü, Weitao; Zhao, Wenbin

doi:10.1049/joe.2018.8367

Cited by 4 publications

(3 citation statements)

References 7 publications

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“…The streaming potential/current can slightly increase with the increase of temperature because the increased temperature enhances ion diffusion in an electrolyte solution (Figure S8). 47 In this study, we did not consider the effect of temperature increment on ion diffusion and the effect of humidity on the evaporation rate in the theoretical estimation based on the previous theoretical model. 45,46 The effects of temperature and humidity increment may give rise to some deviations in the measured electrical outputs compared with the theoretical estimations in Figure 3.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Solar Evaporation-Based Energy Harvesting Using a Leaf-Inspired Energy-Harvesting Foam

Park

Lee

et al. 2021

ACS Sustainable Chem. Eng.

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Sustainable and green energy techniques are in high demand as new energy sources. Over the decades, streaming potential/current has attracted attention as a hydrovoltaic energy technology. However, state-of-the-art technologies have bottlenecks in their practical application. Here, we propose a conductive polymer foam, called leaf-inspired energy-harvesting foam (LIEHF), containing polydimethylsiloxane with macro-and microporous structures homogeneously mixed with conductive carbon materials. The elastic and broadband light-absorbing LIEHF can enhance solar evaporation and generate electricity on the basis of the streaming potential/current used for efficient solar energy conversion with mechanical stability. As a result, a single LIEHF with a size of 15 × 15 × 10 mm 3 can generate electrical outputs with an open-circuit voltage, a short-circuit current, and a power density of 254 mV, 42 μA, and 1 μW cm −2 , respectively, in a sustainable manner under ambient conditions with 1 sun irradiation. The proposed LIEHF outperforms previous carbon-based devices utilizing evaporation-driven streaming potential/current. By connecting to electronic components and microfluidic devices, the proposed LIEHF can be utilized for practical applications, such as in lighting, sensing, and pumping, and as a capacitor charger.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Solar Evaporation-Based Energy Harvesting Using a Leaf-Inspired Energy-Harvesting Foam

Park

Lee

et al. 2021

ACS Sustainable Chem. Eng.

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show abstract

“…Energies 2020, 13, x FOR PEER REVIEW 2 of 12 [12] gave a solution for the streaming current measurements using conductive materials. Consequently, the ECT of pure hydrocarbons and their mixtures [13][14][15], mineral and synthetic oils [16][17][18][19][20][21][22][23][24][25][26][27], natural and synthetic esters [28][29][30], and their mixtures with mineral oil [31,32] were examined. The research results show that the process of mineral oil electrification is very complex and depends on physicochemical properties that change due to temperature, aging processes, humidity, and electric field strength, among others.…”

Section: Methodsmentioning

confidence: 99%

Streaming Electrification Phenomenon of Electrical Insulating Oils for Power Transformers

Zdanowski

2020

Energies

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The subject matter of this study was the problem of the ECT (electrostatic charging tendency) of mineral insulation oils during their flow. The electrostatic charges generated may lead to partial discharges, and as a consequence, to the breakdown of a power transformer insulation system. In this study, the results of the ECT of mineral oils used in transformers were compared. The method of streaming electrification of insulation liquids using a flow-through system was used. The influence of flow speed, temperature, and the pipe material on the values of the electrification current and volume charge density qw were analyzed. The results obtained in this study should be taken into account regarding the operation of power transformers.

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“…For this purpose, a number of measurement methods were prepared to evaluate the risk of streaming electrification in the insulation of transformers. Gao et al [29] have developed a measurement system with a closed insulating liquid circulation, to simulate the oil flow in a transformer. The electrification current was generated in an insulation system model.…”

Section: Streaming Electrification Measurement Methodsmentioning

confidence: 99%

Streaming Electrification of Nycodiel 1255 Synthetic Ester and Trafo EN Mineral Oil Mixtures by Using Rotating Disc Method

Zdanowski¹

2020

Energies

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Power transformers are the main element of an electric power system. The service life of these devices depends to a large extent on the technical condition of their insulation system. Replacing mineral oils with natural or synthetic ester (retrofilling process) may increase the efficiency and operational safety of transformers, and also limit their adverse environmental impact. It is technically unfeasible to completely remove mineral oil from a transformer. Its small residues form a mixture with fluid ester, with different physicochemical and electric properties. Streaming electrification is one of the phenomena which, under unfavorable conditions, may damage the insulation system of a forced oil cooled transformer. It is necessary to run prophylactic tests for the ECT (electrostatic charging tendency) of insulating liquid mixtures from the point of view of transformer retrofilling, which is being used more often than before. The article presents the results of studies on selected physicochemical, and electrical properties, and the ECT of mixtures of fresh and aged Trafo EN mineral oil with Nycodiel 1255 synthetic ester. In this regard, the density, the kinematic viscosity, the conductivity, and the relative dielectric constant were measured. The molecular diffusion coefficient was determined using Adamczewski’s empirical dependency. The streaming electrification was tested in a rotating disc system. The impact of the rotation time, the diameter, and the disc’s rotation speed on the amount of the electrification current generated were analyzed. In addition, the co-relation between the electrification current and the composition of the mixture was determined using fresh and aged mineral oil. On the basis of the electrification model, the volume density of the qw charge was calculated, which is a parameter defining the ECT of insulating liquids. Based on the results, it was concluded that the synthetic ester is characterized by a higher susceptibility to electrification than the mineral oil. However, combining synthetic ester with a small amount (up to 20%) of fresh or aged mineral oil significantly reduces its ECT, which is beneficial from the point of view of retrofilling power transformers.

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Effect of temperature on flow electrification under dc electrical field

Cited by 4 publications

References 7 publications

Solar Evaporation-Based Energy Harvesting Using a Leaf-Inspired Energy-Harvesting Foam

Solar Evaporation-Based Energy Harvesting Using a Leaf-Inspired Energy-Harvesting Foam

Streaming Electrification Phenomenon of Electrical Insulating Oils for Power Transformers

Streaming Electrification of Nycodiel 1255 Synthetic Ester and Trafo EN Mineral Oil Mixtures by Using Rotating Disc Method

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