Experimental data and procedures for predicting thermal conductivity of binary mixtures of nonpolar gases

Abstract

The thermal conductivities of Ne, Ai, Kr, Xe, Hz, 02 Nz, and 0 2 are measured using a thick hot-wire metal cell at five temperatures in the range 40-175OC. The solution of the heat balance equation as developed by Oldham andvluchsinger is employed, and w e estimate an accuracy of 1-2% in our recommended absolute conductivity values. In this temperature range, the thermal conductivities of the binary systems Ne-Hz, Ne-Nn, Ne-02, Hz-Dz, Nz-Dz, Hz-Nz, N2-02, Kr-Hn, Xe-Hz, Xe-Dz, and Xe-Ar are also determined as a function of composition. On the basis of these experimental data, the methods of prediction of thermal conductivity of mixtures due to Hirschfelder, Mason and Saxena, Mathur and Saxena, Lindsay and Bromley, Ulybin et al., and Burgoyne and Weinberg are examined with a view to ascertain their relative accuracies. The framework of Chapman-Enskog kinetic theory in conjunction with the experimental data on thermal conductivity is used to generate the diffusion and viscosity coefficients for Xe-Ar, Xe-Dn, Ne-Hz, Ne-Nn, and Ne-02, as representative systems.R e c e n t l y Saxena and Gupta (26) have reported experimental thermal conductivity data on eight pure gases, four of their binary, two ternary and two quaternary systems as a function of composition. The measurements were taken on a metal hot-wire cell with a thick platinum wire as a hot surface, and a t temperatures of 40", 65", and 93'C.Here we report the thermal conductivities of the binary systems Ne-H2, Ne-N2, Ne-On, HZ-Dn, NZ-DZ, Hn-Nz, Nz-02, Kr-Hz, Xe-H2, Xe-D2, and Xe-Ar as a function of composition and of the related eight pure gases a t 40°, 65", 930, 950, 135", and 175"C, using the same hot-wire cell. The details of the experimental arrangement, procedure of calculation, and comparisons of the experimental conductivity values with some of the semitheoretical procedures are given in the following sections. EXPERIMENTALA metal hot-wire cell of nominal length 10.44 cm and an internal diameter of 0.6412 cm was used for measurements; its details of design, construction, and precision are given by Gambhir et al. ( 3 ) . The cell was connected to a high-vacuum pumping system and could be evacuated to less than cm of mercury pressure. The gas mixtures were made with an accuracy of 20.01% in a specially designed gas-mixing unit [Gambhir and Saxena ( 4 ) ] . The gas or gas mixture was transferred into the cell a t the desired pressure by a mercury lift system. The cell was mounted vertically in a thermostat bath, and the gas was left in it at the desired pressure from 1-4 hr to acquire thermal equilibrium before measurements were taken.Two different thermostat baths were used. The first one is the same as described by Saxena and Gupta (26) and was used for measurements at 40°, 65", and 93°C. Another bath was carefully designed for work a t higher temperatures, and measurements are reported here taken a t 95", 135", and 175°C. A brief description of this bath is given here. It consisted of a cylindrical double-walled stainless steel bath of diameter 20 cm an...

Gaseous transport properties of hydrogen, deuterium and their binary mixtures fromab initiopotential

“…In addition, the viscosity representation of deuterium developed by Assael et al [17] should be considered. Their deviation is þ0.72% at 300 K and it decreases down to þ0.07% at 400 K and up to �4.0% at 2000 K. Figure 5 shows the percentage deviations of dilutegas experimental data [38,39,44,[48][49][50][51][52][53] from the theoretical calculated values for the thermal conductivity of deuterium. Clifford et al [38] derived zero density thermal conductivity data with the THW technique.…”

“…The data presented by Gray et al [48], measured in a hot-wire (HW) instrument under steady-state conditions, show negative differences within �1.6% at room and medium temperatures. Saxena's group [44,[49][50][51][52][53] reported on the most extensive sets of the experimental thermal conductivity data of deuterium. A total of 31 data sets obtained using the HW apparatus cover …”

Models for viscosity, thermal conductivity, and surface tension of selected pure fluids as implemented in REFPROP v10.0

“…(15) being identically zero for noble gases, it is not possible to fit coefficients for fint and the value is Table 3 is a placeholder only. Gas-phase thermal conductivity data from Millat et al (Millat, Ross, Wakeham, & Zalaf, 1988), Saxena and Tondon (Saxena & Tondon, 1971), and Vargaftik and Yakush (Vargaftik & ______________________________________________________________________________________________________ Yakush, 1971) are shown in Figure 171 for comparison purposes. We were unable to locate any liquid-phase thermal conductivity data except for 5 saturated liquid data points over a small temperature range from Bewilogua and Yamashira (Bewilogua & Yamashira, 1972); these were used to obtain the liquid-phase parameters in Table 3.…”

“…The liquid-phase data of Ikenberry and Rice (Ikenberry & Rice, 1963) were used to obtain the coefficients in Table 3. Additional gas-phase data from several sources (Hammerschmidt, 1995;Makhrov & Miroshnichenko, 1984;Saxena & Gupta, 1970;Saxena & Tondon, 1971;Vargaftik & Yakush, 1971;Voshinin, Kerzhentsev, Studnikov, & Yakush, 1975;Zaitseva, 1959) are used for comparison purposes only. Parameters for the critical enhancement are presented in Table 4.…”

Internal forced convection to low-Prandtl-number gas mixtures

“…The few data deviating more than -5% from the correlation were mixture runs with maximum wall U temperatures in excess of 668°C (1234*F) and Tw/Tb > 1. 8 and with modified wall Reynolds numbers in the low range between 8,000 and 20,000. The data deviating more than +5% were all air runs with modified wall Reynolds numbers between 8,500 and 17,500.…”