Binary Diffusion Coefficient Data of Various Gas Systems Determined Using a Loschmidt Cell and Holographic Interferometry

Abstract

The paper reports on binary diffusion coefficient data for the gaseous systems argon–neon, krypton–helium, ammonia–helium, nitrous oxide–nitrogen, and propane–helium measured using a Loschmidt cell combined with holographic interferometry between (293.15 and 353.15) K as well as between (1 and 10) bar. The investigations on the noble gas systems aimed to validate the measurement apparatus by comparing the binary diffusion coefficients measured as a function of temperature and pressure with theoretical data. In previous studies, it was already shown that the raw concentration-dependent data measured with the applied setup are affected by systematic effects if pure gases are used prior to the diffusion process. Hence, the concentration-dependent measurement data were processed to obtain averaged binary diffusion coefficients at a mean mole fraction of 0.5. The data for the molecular gas systems complete literature data on little investigated systems of technical interest and point out the capabilities of the applied measurement apparatus. Further experimental data are reported for the systems argon–helium, krypton–argon, krypton–neon, xenon–helium, xenon–krypton, nitrous oxide–carbon dioxide, and propane–carbon dioxide at 293.15 K, 2 bar, and a mean mole fraction of 0.5.

Appendix: Binary Diffusion Coefficient Data

Table 1 Molar density of the mixture and binary diffusion coefficient data for the different gas systems at a mole fraction of 0.5 and different thermodynamic states

Table 2 Molar density of the mixture and binary diffusion coefficient data at a mole fraction of 0.5 for different gas systems studied at 293.15 K and 2 bar

The $D_{12}$ data discussed in context with the figures presented in Sect. 3 as a function of temperature and pressure are listed in Table 1. In Table 2, the results of the raw data processing for different systems investigated at 293.15 K and 2 bar in a previous study [9] are given. All $D_{12}$ data are reported together with the estimated expanded uncertainties obtained according to the procedure described in Sect. 2.5. Furthermore, the corresponding values for $\rho _{\mathrm{mix}}$ for the different gaseous systems in the particular thermodynamic states are given in the tables. $\rho _{\mathrm{mix}}$ is assumed to be independent of the mole fraction for a given system and thermodynamic state. For the Ar–Ne system, experimentally determined $\rho _{\mathrm{mix}}$ values vary due to real gas effects by less than 0.1 % during the diffusion process. $\rho _{\mathrm{mix}}$ can also be calculated by

$$\begin{aligned} \frac{p}{RT}=\rho _{\mathrm {mix}} +\rho _{\mathrm {mix}}^{2} B_{\mathrm {mix}} +\rho _{\mathrm {mix}}^{3} C_{\mathrm {mix}} . \end{aligned}$$

(11)

Here, $B_{\mathrm{mix}}$ and $C_{\mathrm{mix}}$ denote the second and the third pressure virial coefficient of the mixture and were taken from the literature [1, 10, 14–17]. The $\rho _{\mathrm{mix}}$ data calculated from Eq. 11 for $x=0.5$ deviate by less than 0.1 % from the experimental data and were used to calculate the $D_{12} \rho _{\mathrm{mix}}$ data given in the figures.