Viscosities and thermal conductivities, suitable for heat-transfer calculations, were estimated for about 200 gases in the ground state from 100 to 5000 K and 1-atmosphere pressure. Free radicals were included, but excited states and ions were not. Calculations for the transport coefficients were based upon the Lennard-Jones (12-6) potential for all gases. This potential was selected because: (1) It is one of the most realistic models available and (2) intermolecular force constants can be estimated from physical properties or by other techniques when experimental data are not available; such methods for estimating force constants are not as readily available for other potentials. When experimental viscosity data were available, they were used to obtain the force constants; otherwise the constants were estimated. These constants were then used to calculate both the viscosities and thermal conductivities tabulated in this report. For thermal conductivities of polyatomic gases an Eucken-type correction was made to correct for exchange between internal and translational energies. Though this correction may be rather poor at low temperatures, it becomes more satisfactory with increasing temperature. It was not possible to obtain force constants from experimental thermal conductivity data except for the inert atoms, because most conductivity data are available at low temperatures only (200 to 400 K), the temperature range where the Eucken correction is probably most in error. However, if the same set of force constants is used for both viscosity and thermal conductivity, there is a large degree of cancellation of error when these properties are used in heat-transfer equations such as the Dittus-Boelter equation. It is therefore concluded that the properties tabulated in this report are suitable for heat-transfer calculations of gaseous systems.

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Estimated Viscosities and Thermal Conductivities of Gases at High Temperatures

Transport in non-porous polymeric membranes is based on the so-called ‘solution–diffusion’ concept [1,2]. This model, formulated in the 19th century, is grounded in the works of J. K. Mitchell [3], T. Graham [4] and S. von Wroblewski [5], who demonstrated that the presence of microscopic open pores or capillaries was not a prerequisite for mass transfer through polymeric films (or septa as they were referred to), such as natural rubber. First, Graham in 1829 [4], and then Mitchell in 1831 [3], noted that gases were capable of permeating through non-porous rubber films and that this process was related to gas dissolution and diffusion in the polymeric materials. The currently accepted interpretation of such experiments was given several decades later by Graham [4] (this and other articles from the early history of membrane science have been reproduced, in part, in a special issue of the Journal of Membrane Science) [6]. Because he did not find a monotonic correlation between the rates of transport and the known gas phase diffusion coefficients of the penetrant molecules, Graham concluded that the process of permeation comprised two stages: sorption of gas by the rubber ‘that must depend upon a kind of chemical affinity’ and diffusion of the sorbed gas molecules [4]. The sorbed gas, as he wrote, ‘comes to evaporate . . . . and reappears as gas on the other side of the membrane. Such evaporation is the same into vacuum and into another gas, being equally gas-diffusion in both circumstances’ [4]. Empirical observations of the pressure and thickness dependence of the steady-state gas permeation rate or flux, N, led von Wroblewski [5] to propose the following relation:

Transport of Gases and Vapors in Glassy and Rubbery Polymers

Investigations into the O 18 -abundance in the precipitation from a warm front reveal a distinct process of fractionation explainable by the unequal pressures of the saturated vapours of H 2 O 16 and H 2 O 18 . An explanation is given of the low O 18 -abundance in glacial waters. A method of experimental investigation into the mechanism of the process of precipitation is discussed. DOI: 10.1111/j.2153-3490.1953.tb01076.x

https://www.tandfonline.com/doi/pdf/10.3402/tellusa.v5i4.8697

The Abundance of O 18 in Atmospheric Water and Water Vapour

We report chemical shift measurements of the hydroxyl protons in methanol and ethanol up to 450 °C and over a wide range of pressures. The extent of hydrogen bonding compared to room temperature co...

Are There Hydrogen Bonds in Supercritical Methanol and Ethanol

We present modifications to an extended corresponding states (ECS) model for thermal conductivity and viscosity originally developed by Ely and Hanley (Ind. Eng. Chem. Fundam. 1981, 20, 323-332). We apply the method to 17 pure refrigerants and present coefficients for the model and comparisons with experimental data. The average absolute viscosity deviation for the 17 pure fluids studied ranges from a low of 0.56% for R236ea to a high of 5.68% for propylene, with an average absolute deviation for all fluids of 3.13% based on a total of 3737 points. The average absolute thermal conductivity deviation for the 17 pure fluids studied ranges from a low of 1.37% for R116 to a high of 6.78% for R115, with an average absolute deviation for all fluids of 3.75% based on a total of 12 156 points. We also present a new correlation for the viscosity of R134a (1,1,1,2-tetrafluoroethane), which is used as a reference fluid for the description of properties of some refrigerants. The new correlation represents the viscosity to within the uncertainty of the best experimental data.

Model for the Viscosity and Thermal Conductivity of Refrigerants, Including a New Correlation for the Viscosity of R134a

(1) An apparatus, based on the principle of Trautz and Weizel, was constructed for measuring the viscosity of vapours. (2) With this apparatus the viscosity of vapours of the following substances were measured at temperatures between about 120° and 300°C.: air, n-pentane, n-hexane, hexamethylene, benzene, methyl acetate, ethyl acetate, ethyl ether, methyl alcohol, ethyl alcohol, n-propyl alcohol, iso-propyl alcohol, acetone, chloroform, carbon tetrachloride and carbon disulphide. (3) From these measurements the constants of both Sutherland and Reinganum as well as collision diameters of molecules were calculated. (4) The collision diameters calculated from viscosity data were found to be nearly equal to those computed from the constants b in the van der Waals equation and they came out to be proportional to the cube roots of molecular volumes at boiling points, as was already pointed out in the preceding paper except few cases. (5) Values obtained for collision diameters of non-polar compounds such as car...

Toshizo Titani

Papers

The viscosity of vapours of organic compounds. part iii

Austausch der Wasserstoffatome zwischen Pyrrol und Wasser. (Vorläufige Mitteilung)

Austauschreaktion der Kernwasserstoffatome des Phenols. I. Austauschreaktion in alkalischer Lösung

Isotopenaustausch zwischen wasser und einigen organischen verbindungen

DER ISOTOPENAUSTAUSCH ZWISCHEN ANILIN CHLORHYDRAT UND SCHWEREM WASSER (Vorläufige Mitteilung)