PROPERTIES OF LIQUIDS
The Liquid Properties Laboratory’s mission is to develop, maintain and disseminate units of density, viscosity and surface tension, as well as the development and implementation of new methods and measurement capabilities.
In the frame of its activities has as its main concerns:
- development, preparation and certification of liquid reference materials for these quantities;
- participation and coordination of interlaboratory comparisons;
- carrying out measurement audits for: the calibration of hydrometers, oscillation-tube density meters and capillary viscometers and for determining the density, viscosity and surface tension of liquids;
- performing calibrations of hydrometers; oscillation-tube density meters; viscometers (capillary, rotational and Stabinger’s); rheometers and tensiometers, for accredited laboratories;
- determination of density, surface tension, viscosity and rheological parameters of liquid samples;
- carrying out training courses on metrology of liquid properties;
- participation in national and international development and research projects.
Get to know here ongoing projects.
The areas of activity for which the Laboratory of Properties of Liquids has international recognition, are:
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- Density of liquids: for the calibration of glass hydrometers, at the reference temperature of 20°C, by the Cuckow method, in the interval from 750 kg m-3 to 1 000 kg m-3, with an expanded uncertainty of 0,1 kg m-3;
- Kinematic viscosity of newtonian liquids, determined using capillary viscometers, at a reference temperature of 20°C, in the interval from 1,2 mm2 s-1 to 17 000 mm2s-1, with a relative expanded uncertainty of 0.16 % – 0.46%;
- Dynamic viscosity of Newtonian liquids, determined using capillary viscometers, at a reference temperature of 20°C, in the interval from 0,89mPa s to 15 000 mPa s, with a relative expanded uncertainty of 0.45% – 1.0%;
- Capillary viscometer constant, at a reference temperature of 20°C, in the interval from of 0,001 mm2s-2 to 30 mm2 s-2, with a relative expanded uncertainty of 0,65%.
In an advanced stage of obtaining international recognition:
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- Density of liquids, by the hydrostatic weighing method, at a reference temperature of 20°C, in the interval from 600 kg m-3 to 2 000 kg m-3 (future participation in international comparison);
- Density of liquids: for the calibration of glass hydrometers at the reference temperature of 20°C, using the Cuckow Method, in the interval from of 600 kg m-3 to 2 000 kg m-3 (for obtaining satisfactory results in the comparison international EURAMET.MD-K4.2020 / EURAMET Project No. 1496);
- Density of liquids, by densimetry of vibrant tube densimeters, from 15°C to 40°C, in the interval from 750 kg m-3 to 1 000 kg m-3 (for obtaining satisfactory results in the international comparison EURAMET Project 1240);
- Kinematic viscosity of Newtonian liquids, determined using capillary viscometers, at a reference temperature of 15°C, in the interval from 1,2 mm2s-1 to 17 000 mm2 s-1, with a relative expanded uncertainty of 0.16 % – 0.29% (for obtaining satisfactory results in the Key Comparison CCM.V-K3);
- Surface tension of liquids, to determine the surface tension of liquids (future participation in international comparison).
Density, r
kilogram per cubic meter, kg m-3
Defined as the mass per unit volume of a substance at a given temperature and pressure.
Kinematic viscosity, ν
Square meter per second, m2 s-1
Defined as the resistance to flow of a fluid under gravity.
Viscosity, dynamic viscosity, h
Pascal second, Pa s
Ratio between the applied shear stress and shear rate. It is sometimes called the coefficient of dynamic viscosity, or simply viscosity. Thus, dynamic viscosity is a measure of the resistance to flow or deformation of a liquid
Surface tension, s
Newton per meter, N m-1
Force perpendicular to a line element in a surface divided by the length of the line.
External documents and Links:
Get to know here available calibration services on the liquid properties laboratory.
International Recognition
Calibration services listed are registered as Calibration and Measurement Capabilities (CMCs) in the BIPM database.
