Recommended Viscosities of 11 Dilute Gases at 25 °C

Abstract

Commercially manufactured meters that measure the flow of a process gas are often calibrated with a known flow of a surrogate gas. This requires an accurate model of the flow meter and accurate values of the relevant thermophysical properties for both gases. In particular, calibrating a "laminar" flow meter near ambient temperature and pressure requires that the ratio (process gas viscosity)/(surrogate gas viscosity) be known to approximately 0.1%. With this motivation, we critically reviewed measurements of viscosity conducted with 18 instruments near 25°C and zero density for 11 gases: He,

Measurements of the viscosity of carbon dioxide at temperatures from (253.15 to 473.15)K with pressures up to 1.2MPa

“…A similar effect was discovered by Berg and Moldover [5] in the data set published by Evers et al [3]. Deviations of the data from Evers et al [3] from the values published by Berg and Moldover [5] are shown in figure 3. Further details concerning figure 3 are discussed below.…”

“…(2) The FIGURE 3. Relative deviations of the experimental viscosity data of Evers et al [3] and of this work (both extrapolated to zero density) from recommended values published by Berg and Moldover [5] at zero density plotted vs. viscosity. s, Evers et al [3]; 4, This work with experimentally determined residual damping; h, This work with calibrated residual damping.…”

“…?, Change in the data of this work due to the calibration of the residual damping; -Á -, Linear fit to Evers' deviations, which seem to depend on viscosity; ----, Linear fit to the uncalibrated data of this work, which seem to depend on viscosity, too. This figure is based on a figure published by Berg and Moldover [5]. compensation of the viscosity dependent offset revealed the same offset of the damping D for all measured gases.…”

“…Docter et al [2] applied the same approach using nitrogen as reference fluid. However, we followed Berg and Moldover [5], who recommended this practice with helium as reference fluid. Cencek et al [6] claim a relative standard uncertainty of only 0.001% for their zero density viscosities of helium, which were calculated ab initio.…”

Viscosity of gaseous ethyl fluoride (HFC-161)

“…According to Berg and Moldover [7], the viscosities of dilute gases at 25 C have high accuracy. The values of viscosity and density of argon, carbon dioxide, nitrogen and hydrogen were taken from literature [7][8][9][10][11][12]. The result of the calibration is plotted in Fig.…”