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Analysis of Thermal Field in Mineral Transformer Oil Based Magnetic Fluids

100%

Kosterec M., Kurimský J., Cimbala R., Čonka Z., Kruželák L., Rajňák M., Timko M., Kopčanský P., Vargová B.

Acta Physica Polonica A

2017

vol. 131

issue 4

937-939

Growing interest in the use of magnetic fluids in power systems especially in transformers as insulation and a coolant is nowadays registered. Magnetisable nanofluids, which are used in cooling systems as an alternative to mineral transformer oil, are characterized by lower concentration of magnetic nanoparticles. The magnetic fluid has better heat transfer and dielectric properties such as breakdown than mineral transformer oil and it can be used to improve heat flow, thereby increasing the ability of the active parts to resist failures such as electromagnetic pulses. External magnetic field may be used for forced circulation of magnetic fluid. Magnetic force inside the magnetic fluid can be adequately controlled by adjusting the incident magnetic field. This paper presents thermal distribution, fluid flow and cooling ability of mineral transformer oil and magnetic fluid based on mineral transformer oil. The concentration of Fe₃O₄ magnetic nanoparticles is 0.15% volume of mineral transformer oil. The thermal field is generated by a steel conductor. Thermal distributions in mineral transformer oil and magnetic fluid are investigated and differences for both cases are discussed in the paper.

Variation of Magnetic Fluid Deformation Related to Nanoparticle Concentration in Steady Electric Field

81%

Kosterec M., Kurimský J., Cimbala R., Špes M., Farkaš R., Dolník B., Gamcová M., Rajňák M., Timko M., Kopčanský P., Paulovičová K., Vargová B.

Acta Physica Polonica A

2018

vol. 133

issue 3

570-573

Today, it is important to know the behaviour of magnetic fluids applied in the power electrical machines, e.g. in power transformers, when exposed to an electric field. Besides their promising applications in high voltage engineering, they are of increasing interest from designed assembly and pattern formation point of view. The structure of such magnetic fluids is easily controllable by external magnetic fields. However, less attention has been paid to structural phenomena in magnetic fluids induced by electric fields. The core of this paper is dedicated to the experimental observation of a magnetic fluid droplet deformation in a steady electric field. The mutual relation between the deformation parameter and magnetic nanoparticles concentration is analysed. Spatio-temporal analysis of the droplet shape is presented in the paper. The phenomena of the droplet deformation were recorded by a camera. The detailed experimental procedure is presented. The method of deformation parameter calculation based on the linear pixel as the smallest-size unit in digital image is written. Finally, the relation between the deformation parameter and the nanoparticle volume concentration, as well as the time and magnitude of the DC field application are thoroughly evaluated. The results show that the deformation parameter decreases with increasing concentration at constant applied steady electric field but increases with increasing applied steady electric field.

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2 Acta Physica Polonica A

1 2018

1 2017

2 Cimbala R.

2 Kopčanský P.

2 Kosterec M.

2 Kurimský J.

2 Rajňák M.

2 Timko M.

2 Vargová B.

1 Dolník B.

1 Farkaš R.

1 Gamcová M.

1 Kruželák L.

1 Paulovičová K.

1 Čonka Z.

1 Špes M.

Search results

Analysis of Thermal Field in Mineral Transformer Oil Based Magnetic Fluids

Variation of Magnetic Fluid Deformation Related to Nanoparticle Concentration in Steady Electric Field