Capillary Viscometer and Vibrating Tube Densimeter for Simultaneous Measurements up to 70 MPa and 423 K

New equipment has been designed and constructed to simultaneously measure dynamic viscosity and density on the basis of capillary flow technique and vibrating tube method, respectively, up to 70 MPa and 423.15 K. This apparatus has been built taking into account a number of physical parameters such as volumetric flow, length, and inner radius of the capillary tube and border effects. On the basis of the results of this work, densities for liquids are measured with relative combined expanded uncertainties of 0.07 % for water and ethanol, 0.7 % for hexane, 0.2 % for heptane, and 0.17 % for 1-pentanol and 1-heptanol. For the dynamic viscosity, the corresponding relative combined expanded uncertainties are 0.7 % for water and ethanol, 4.0 % for hexane, and 1.1 % for heptane, 1-pentanol, and 1-heptanol. In the calculated uncertainty for density and dynamic viscosity was included the contribution of the sample impurity. Experimental determinations of both dynamic viscosities and densities are performed, for several pure liquids, at the same conditions of temperature, pressure, and volumetric flow and recorded by means of an electronic device. Data reliability has been verified comparing the measured values with the available literature data for carbon dioxide, water, heptane, and ethanol up to 353 K and 30 MPa. The maximum deviations of the measured data compared to the literature data are ± 3 μPa·s for dynamic viscosity and ± 0.25 kg·m^-3 for density. Furthermore, new experimental data are reported for hexane, 1-pentanol, and 1-heptanol up to 353 K and 30 MPa with a combined expanded uncertainty mentioned before.