The ferro-oils viscosity depended simultaneously on the temperature and magnetic oil particles concentration η = η(t,ϕ). Part 2

The purpose of this article is to determine and describe the viscosity characteristics of the ferro-oils at context of temperature changes depend on different concentrations of magnetic particles. These characteristics were determined for the following test conditions: atmospheric pressure, constant shear rate and absent of an external magnetic field. In Part I of the paper there was determined and described four mathematical-physical models of fittings of the viscosity characteristics: exponential, fourth-degree polynomial and two homographic models – second- and third-degree. In present Part II of the paper above mentioned models have been developed. That has been done their depending on parameter of concentrations of magnetic particles ϕ in ferro-oil. There have 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. 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 Pennzoil 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. 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 such as 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.

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Opracowanie ze środków MNiSW w ramach umowy 812/P-DUN/2016 na działalność upowszechniającą naukę.