Marcin Frycz

EFFECT OF CONCENTRATION OF MAGNETIC PARTICLES ON FERROOIL'S DYNAMIC VISCOSITY AS A FUNCTION OF TEMPERATURE AND SHEAR RATE

Ferrooil’s dynamic viscosity changes significantly alter the tribological properties and thus its usefulness as a lubricant of the sliding journal bearings. Due to the fact that the ferrooil demonstrate strong magnetic polarity in the presence of an external magnetic field, it is possible to control the viscosity by means of an external magnetic field just by changing the intensity as well as by changing of the concentration of magnetic particles. There is presented an effect of the changes of the concentration of magnetic particles included in the ferrooil on the dynamic viscosity in the absence of external magnetic field in this paper. The study was conducted in the context of temperature’s and shear rate’s changes. In that way, it was also taken into account the influence of external physical conditions of ferrooil’s employment. Tests were performed on HAAKE MARS III rheometer for the shear rate range from 0 to 100000 1/s and temperature of work to 120oC and the tested ferrofluid was product of FerroTec of Unterensingen (Germany), which is a mixture of colloidal mineral motor oil Penzzoil’s LongLife Golds SAE 15W-40 with Fe 3O4 magnetic particles at a concentrations of: 8, 6, 4, 3, 2 and 1% and the surfactant. Addition of surfactant is to prevent clustering of magnetic particles in the oil. The paper presents, in the form of graphs, the changes of ferrooil’s dynamic viscosity as a function of temperature, shear rate and concentration of magnetic particles. The results of research were also subjected to analysis. This work is part of a wider study on the analysis of changes in operating parameters of journal bearing ferrofluid’s lubricated.

MODELS OF VISCOSITY CHARACTERISTICS ŋ=ŋ(B) OF FERRO-OIL WITH DIFFERENT CONCENTRATION OF MAGNETIC PARTICLES IN THE PRESENCE OF EXTERNAL MAGNETIC FIELD

The purpose of this article is to determine, identify and describe the viscosity characteristics of the ferro-oil with different concentrations of magnetic particles in the presence of an external magnetic field interaction. These characteristics are defined in the context of magnetic induction changes. These rheological tests were performed on a Physica MCR 301 rheometer. It was used a measuring system ‘plate to plate’ type which was armed with magneto-rheological research system MRD 180/1T. The tests were performed for the selected temperature of the medium i.e. 90°C, the shear rate changes were carried from 0 to 1000 1/s. Changes of the magnetic field intensity value were ranged from 0 to 500 mT. The selected concentrations of magnetic particles in a ferro-oil were 1%, 2%, 4%, 6% and 8% and the tested ferro-oil was product of FerroTec of Unterensingen (Germany), which is a mixture of colloidal mineral motor oil Penzzoil’s LongLife Golds SAE 15W-40 with Fe3O4 magnetic particles and the surfactant. Analyses of the results, identify and matching characteristic were calculated using STATISTICA software. It has been proposed three categories of functions mapping the waveforms of the results obtained experimentally: the exponential function, logarithmic with basis of the normal and the polynomial function.

The ferro-oils viscosity depended simultaneously on the temperature and magnetic oil particles concentration η = η(t,ϕ). Part 1

The purpose of this article is to determine, identify and describe the viscosity characteristics of the ferro-oil with different concentrations of magnetic particles at context of temperature changes. These characteristics were determined for the following test conditions: atmospheric pressure, constant shear rate and absent of an external magnetic field. Tests were performed for selected concentrations of magnetic particles in ferro-oil ranging: 1%, 2%, 4%, 6% and 8%. Tested ferro-oil was product from Unterensingen FerroTec Company (Germany) which is a mixture of colloidal mineral engine oil LongLife Gold Penzzoil class SAE 15W-40 with addition of Fe3O4 magnetic particles and a surfactant. Analysis of the results, identifying and fitting of characteristics has been made by means of software StatSoft STATISTICA ver.9.1. There has been also undertaken comparison of the accuracy of estimation of reached results by selected mathematical models as well as these results have been rated according to their compliance with theoretical assumptions. Moreover, the waveform parameters of functions have been determined and their assessed quality has been done also. The obtained characteristics going to be used by author in his future work to build mathematical models of viscosity changes of ferro-oils in the aspect of changes of parameters like temperature, pressure, shear rate and the value of the external magnetic field. The determined parameters of physical properties will be used in analytical and numerical studies of flow and operating parameters of slide journal bearings lubricated with ferro-oils.

Effect of the Concentration of the Magnetic Particles in the Ferrooil on its Dynamic’s Viscosity Changes in an External Magnetic Field

There is presented an effect of the changes of the concentration of magnetic particles included in the ferrooil on the dynamic viscosity in the presence of external magnetic field in this paper. The study was conducted in the context of temperature’s changes. In that way, the influence of external physical conditions of ferrooil’s employment was also taken into account. Ferrooil’s dynamic viscosity changes significantly alter the tribological properties and thus its usefulness as a lubricant of the sliding journal bearings. Due to the fact that the ferrooil demonstrates strong magnetic polarity in the presence of an external magnetic field, it is possible to control the viscosity by means of an external magnetic field just by changing the intensity as well as by changing of the concentration of magnetic particles.The paper presents, in the form of graphs, the changes of ferrooil’s dynamic viscosity as a function of temperature and concentration of magnetic particles. The results of research were also subjected to analysis.