S.T. Ro

Viscosity of the Noble Gases in the Temperature Range 25–700°C

New relative measurements of the viscosity of xenon at a pressure P=1 atm and in the temperature range T=25–700°C are reported. The viscosity of argon has also been remeasured. A careful analysis of the long‐term reproducibility of the oscillating‐disk viscometer employed in the work is presented together with best estimates of the viscosity of all the noble gases. Standard reference values of the viscosity of the gases at atmospheric pressure and at zero density at 25°C are given. The data for all the monatomic gases are represented by means of a single empirical correlation.

An extended law of corresponding states for the equilibrium and transport properties of the noble gases

Abstract This paper proposes a new law of corresponding states which provides us with a thermodynamically consistent and accurate correlation of the properties B , μ, k , b , D , μ 12 , k 12 , D 12 , B 12 for the monatomic gases and their binary mixtures. The law of corresponding states, based on the hypothesis that all monatomic gases obey the same two-parameter pair potential, leads to the empirical determination of a number of universal functionals which replace the corresponding integrals of the Chapman-Enskog theory. The use of these functionals together with a list of empirically determined scaling factors for pure gases and binary mixtures allows us to compute the above quantities over an unusually large range of temperatures and a modest range of pressures, thus making it possible to employ measurements of a limited class of properties in a limited range of states to compute all others over wider ranges of states, as well as utilizing data on one gas, to generate them for another. Judged from the practical point of view of a user, the correlation is accurate and complete as far as monatomic gases and their binary mixtures are concerned, except for the evaluation of the pressure effect on the transport properties of mixtures. Taking into account the fact that the specific heat, c v , (or, equivalently, c v ) is a constant, and that it together with the equation Pv = RT + BP [or, equivalently, Pv = RT (1 + B/v )] fully determines all equilibrium properties of a monatomic gas in a reasonable range of pressures and a wide range of temperatures, the paper provides the basis for a thermodynamically consistent formulation of equilibrium as well as transport properties of the monatomic gases and their binary mixtures. The law of corresponding states provides us also with a sharp criterion which permits us to disqualify guessed analytic forms of the pair potential. It turns out that no member of the ( n -6) family of potentials is adequate, but that the (11-6-8) potential proposed by Klein and Hanley is acceptable as a correlator of data (for 1 ≤ T ∗ ≤ 20), even though it leads to considerably more complex numerical calculations. Even this potential fails for helium at high reduced temperatures.

The viscosity and diffusion coefficients of eighteen binary gaseous systems

The paper reports accurate measurements of the viscosity of the eighteen binary gaseous systems: CF4 with He, Ne, Ar, N2, CO2, CH4; SF6 with He, Ne, Ar, N2, CO2, CH4, CF4 and O2 with He, Ne, CO2, CF4, SF6. The measurements were performed in a high-precision oscillating-disk viscometer at atmospheric pressure and in the temperature range 25–200°C for the systems containing CH4 or SF6 and in the temperature range 25–400°C for the remainder. The reported viscosities are believed to be accurate to within ±0.1% at room temperature and to within ±0.2% at 400°C.

Viscosity of the Binary Gaseous Mixtures He–Ne and Ne–N2 in the Temperature Range 25–700°C

The paper presents new relative measurements of the viscosity of the binary mixtures He–Ne and Ne–N2, as well as repeated determinations of the viscosity of the pure gases. The experiments were performed using an oscillating‐disk viscometer; they were made at atmospheric pressure and in the nominal temperature range 25–700°C. The accuracy of the measurements is one of ± 0.1% at 25°C, deteriorating to ± 0.3% at 700°C. Tables of the thermal conductivity of the monatomic‐gas mixture are provided together with values for pure nitrogen. The binary diffusion coefficients for the mixtures have also been computed.

Viscosity of the Binary Gaseous Mixture Helium‐Nitrogen

The paper presents new relative measurements of the viscosity of binary mixtures of helium and nitrogen, together with repeated determinations of the viscosity of the pure gases. The experiments were performed, using an oscillating disk viscometer; they were made at atmospheric pressure and in the nominal temperature range 25–700°C, the precision being one of ±0.1%. Tables of thermodynamically consistent values of the thermal conductivity of the pure gases are given. The binary diffusion coefficient for the mixture has also been computed.

The viscosity of CH4, CF4 and SF6 over a range of temperatures

Abstract The paper contains new measurements of the low-density vicosity of CH 4 (25–200°C), CF 4 (25–600°C) and SF 6 (25–300°C). It is believed that the data are accurate to ±0.1% at 25°C and to ±0.3% at 600°C. The data can be interpolated (and, probably, also extrapolated) with the aid of our extensive law of corresponding states formulated earlier in this laboratory.

The viscosity of oxygen and of some of its mixtures with other gases

Abstract The paper reports new measurements of the viscosity of oxygen and air, and of the binary mixtures O2-Ar, O2-Kr and N2-O2, together with check values for the pure gases which appear in them. The measurements were performed in an oscillating-disk viscometer at atmospheric pressure and extrapolated to zero density. The nominal temperature range is 25–600°C, and the precision deteriorates from ±0.1% at 25°C to ±0.3% at 600°C. The experimental results are interpreted in terms of the Chapman-Enskog theory and the law of corresponding states due to Kestin, Ro and Wakeham. All tests show that the synthesis thus provided “predicts” the measured values with an uncertainty which does not exceed ±0.5% in most cases. The data yield new values of the binary diffusion coefficients of the mixtures, but do not permit us to calculate the thermal conductivity. Nevertheless, the analysis makes it plausible that Keyess correlation for the thermal conductivity of oxygen might be acceptable.

Viscosity of Carbon Dioxide in the Temperature Range 25–700°C

The paper presents new relative measurements of the viscosity of carbon dioxide at a pressure P=1 atm and in the temperature range 25–700°C. The accuracy of the reported viscosity data is estimated as ±0.1% at 25°C and ±0.3% at 700°C. The rotational collision number for carbon dioxide is computed with the aid of the kinetic theory for polyatomic gases and reliable thermal conductivity data.

Viscosity of the Binary Gaseous Mixture Neon‐Krypton

The paper presents new relative measurements of the viscosity of binary mixtures of neon and krypton, and repeated determinations of the viscosity of the pure gases neon, krypton, and argon. The experiments were performed using an oscillating disk viscometer; the measurements were made at atmospheric pressure and in the nominal temperature range 25–700°C and with a precision of ±0.1%. Tables of consistent values of the thermal conductivity of the mixture as well as of the pure gases are given. The binary diffusion coefficient for the mixture has also been computed.

On the properties of multicomponent mixtures of monatomic gases

Abstract The paper examines possible extensions of the law of corresponding states which was proposed recently by Kestin, Ro and Wakeham. It is generally concluded that the paper contains a complete solution to the problem of calculating the low-density properties (regime governed by binary collisions) of the monatomic gases and of their multicomponent mixtures over the complete temperature range, excepting quantum and ionization effects. This extension is specifically tested with respect to Rutherfords new measurements of isotopic thermal-diffusion factors and of our own measurements of the viscosity of four ternary mixtures of Ne-Ar-Kr over a wide range of temperatures.