Thermal Conductivities of Rare Gas Mixtures

Abstract

Recent measurements of the thermal conductivities of all ten possible binary mixtures of the rare gases and of the ternary mixture He–Kr–Xe at 29° and 520°C are compared with theoretical calculations. Three calculations are carried out, based on: (1) rigorous kinetic theory, (2) an approximate formula which uses only conductivities of the pure components, and (3) a new semiempirical formula which also requires knowledge of the conductivity of one composition of binary mixture. The agreement is generally satisfactory and furnishes support for the usefulness and accuracy of the formulas used.

Comments on the Ulybinet al.method of calculating thermal conductivities of mixtures of chemically non-reacting gases at ordinary pressures

“…29~ and 520~ [5,10,11,13]. To be compatible with the calculations of Ulybin et al [1] we quote the percentage deviations between the experimental and computed values of kmix at 520~ which are found when ~ij determined at 29% are used.…”

“…As ~lj" are assumed, and are found [9,12] to be fairly independent of temperature, kmix value at any convenient temperature may be used to determine ~ij and ~jl. We refer to the methods of Mason and yon Ubisch [5], Saxena and Gambhir [8], and Gambhir and Saxena [9] below as I, II and III respectively for the sake of brevity.…”

“…A fair assessment of the Ulybin et al method really involves its comparison with such methods which require similar information and indeed several such semi-empirical procedures have been developed on the base of equation (3). In particular, we consider the semiempirical procedures due to Mason and yon Ubisch [5] developed for'mixtures of rare gases and successfully extended to mixtures of gases involving polyatomic, and polar gases by Mathur and Saxena [6], and Tondon and Saxena [7] respectively. We also consider two other procedures which are due to Saxena and Gambhir [8], and Gambhir and Saxena [9] and have been tested by detailed calculations on mixtures of rare gases [10,11].…”

“…The detailed calculations for the experimental data of von Ubisch [5] are available for all the methods and at both temperatures of measurements, viz. 29~ and 520~ [5,10,11,13].…”

Investigation of the Cause of Low Blister Threshold Temperatures in the RERTR-12 and AFIP-4 Experiments

“…This result is used in the FLUENT model to account for the effect of fuel porosity on the thermal conductivity of the fuel foil, as described below. The pores are assumed to be filled with a mixture of 90% Xe and 10% Kr [5], the thermal conductivity of which has been measured [12]. The thermal conductivity of fuel containing pores is obtained from a formula for properties of a two-phase mixture [13].…”