The choice of materials for the production of new reference materials of liquid viscosity certified in the interval of allowed temperature values from -40 °C to -5 °C

The article presents the results of research aimed at the selection of materials for the production of new reference materials intendedfor verification, calibration, and testing for type approval of means of measuring the viscosity of liquids, as well as certification of methods for measuring the viscosity of liquid media at temperatures below 0 °C. The developed reference materials are certified in the interval of allowed temperature values from -40 °C to -5 °C. This allows providing a wide range of modern methods for measuring the viscosity of liquids such as glass capillary viscometers, rotational viscometers, rheometers, etc.

Comparison tests for the determination of the viscosity values of reference liquids by capillary viscometers and stabinger viscometer SVM 3001

The present study was realized for measuring viscosities of reference liquids using capillary viscometers and Stabinger viscometer SVM 3001 with viscosity interval between 1 mm2/s and 5000 mm2/s with temperatures from 20 °C to 80 °C. Based on our measurement with various liquids, we determine the viscosity values and compare both of the results. The aim of this study to evaluate the results of the primary level viscosity measurement system and stabinger viscometer and to compare the measurement results due to the providing traceability of Stabinger viscometer by TUBITAK UME. An increasing number of national metrology institutes and accredited laboratories provide viscometer calibration with reference liquids in a wide viscosity range. It is a common practice to use the viscosity of water as the metrological basic of viscometry. The national standard of viscosity provided by TUBITAK UME consists of a set of ubbelohde viscometers covering the measuring range of kinematic viscosities from about 0.5 mm2/s to 100 000 mm2/s. At the low viscosity, long − capillary viscometers are used as primary standards which are directly calibrated water.

VISCOSITY OF TERNARY SOLUTIONS COMPOSED OF PROPYLENE GLYCOL, ETHANOL AND WATER

This paper presents the experimental data on the kinematic viscosity of water / ethanol / propylene glycol solutions that are prospective as coolants. An experimental setup with capillary viscometers was used to measure the kinematic viscosity of samples in the temperature range from 243K to 303K and in the wide range of mass fractions of components. Experimental uncertainty of the obtained experimental data does not exceed 0.4 %. Solutions compositions were chosen according to needs of the refrigeration industry in order to provide a possibility of their application at temperatures 233 K and higher. The new model for prediction of the kinematic viscosity of coolants within wide interval of reduced temperatures 0.1 ≤ ≤ 0.6 ( is the pseudocritical temperature) based on the limited experimental data both for pure substances and aqueous solutions of mono- and polyalcohols is presented in paper.