ACTA

Rheological and Thermal Transport Characteristics of a Transformer Oil Based Ferrofluid

K. Paulovičová^a, J. Tóthová^b, M. Rajňák^a,b, Z. Wu^c, B. Sundén^c, L. Wadsö^d, T. Tobiáš^a, P. Kopčanský^a, M. Timko^a and V. Lisý^b
^aInstitute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, Košice, Slovakia
^bFaculty of Electrical Engineering and Informatics, Technical University of Košice, Letná 9, Košice, Slovakia
^cDepartment of Energy Sciences, Lund University, 22100 Lund, Sweden
^d Division of Building Materials, Lund University, 22100 Lund, Sweden

Full Text PDF

Ferrofluids based on insulating liquids are intensively studied as a potential substitute of liquid dielectric in high voltage technologies. In this work we focus on the experimental investigation of flow and thermal transport characteristics of a ferrofluid based on transformer oil (Mogul) and iron oxide nanoparticles. The magneto-rheological behavior of the ferrofluid was studied by a rotational rheometer in the shear rate range from 1 to 1000 s^-1 and magnetic field up to 1 T. By means of a thermal constants analyzer and a transient plane source method we obtained the thermal conductivity, specific heat and thermal diffusivity values for the studied oil and the ferrofluid. It is shown that the Newtonian character of the ferrofluid changes to a non-Newtonian with application of the magnetic field. The notable magneto-viscous effect has been observed especially at low shear rates. We found that the doping of the transformer oil by 3 wt% of the nanoparticles results in a thermal conductivity enhancement by about 3.2%.

DOI: 10.12693/APhysPolA.133.564
PACS numbers: 47.65.Cb, 83.80.Gv, 66.20.Ej, 44.35.+c