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Medientyp:
E-Artikel
Titel:
Density Measurements of an Air-Like Binary Mixture over the Temperature Range from 100 K to 298.15 K at Pressures up to 8.0 MPa
Beteiligte:
von Preetzmann, Nils;
Kleinrahm, Reiner;
Eckmann, Philipp;
Cavuoto, Giuseppe;
Richter, Markus
Erschienen:
Springer Science and Business Media LLC, 2021
Erschienen in:International Journal of Thermophysics
Sprache:
Englisch
DOI:
10.1007/s10765-021-02871-4
ISSN:
0195-928X;
1572-9567
Entstehung:
Anmerkungen:
Beschreibung:
<jats:title>Abstract</jats:title><jats:p>Densities of an air-like binary mixture (0.2094 oxygen + 0.7906 nitrogen, mole fractions) were measured along six isotherms over the temperature range from 100 K to 298.15 K at pressures up to 8.0 MPa, using a low-temperature single-sinker magnetic suspension densimeter. The measurements were carried out at <jats:italic>T</jats:italic> = (100, 115, and 130) K in the homogeneous gas and liquid region, and at <jats:italic>T</jats:italic> = (145, 220, and 298.15) K in the supercritical region (critical temperature <jats:italic>T</jats:italic><jats:sub>C</jats:sub> = 132.35 K); in total, we present results for 52 (<jats:italic>T</jats:italic>, <jats:italic>p</jats:italic>) state points. The relative expanded combined uncertainty (<jats:italic>k</jats:italic> = 2) of the experimental densities was estimated to be between 0.03 % and 0.13 %, except for four values near the critical point. The largest error is caused by the magnetic suspension coupling in combination with the mixture component oxygen, which is strongly paramagnetic; the resulting force transmission error is up to 1.1 %. However, this error can be corrected with a proven correction model to an uncertainty contribution in density of less than 0.044 %. Due to a supercritical liquefaction procedure and the integration of a special VLE-cell, it was possible to measure densities in the homogeneous liquid phase without changing the composition of the liquefied mixture. Moreover, saturated liquid and saturated vapor densities were determined at <jats:italic>T</jats:italic> = (100, 115, and 130) K by extrapolation of the experimental single-phase densities to the saturation pressure. The new experimental results were compared with the mixture model of Lemmon <jats:italic>et al</jats:italic>. for the system (nitrogen + argon + oxygen) and the GERG-2008 equation of state.</jats:p>