Thermal conductivity of methyl and butyl propionates at various temperatures and pressures

Experimental data are presented on the thermal conductivities of methyl and butyl propionates in the liquid and gaseous phases, including the saturation line, over the temperature range 300–600°K and pressures of 0.1–50 MPa.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 43, No. 4, pp. 626–630, October, 1982.     

Thermal conductivity of sandstone at high pressures and temperatures

Results are given of experimental investigations of the coefficient of thermal conductivity of samples of sandstone at hydrostatic pressures of up to 400 MPa and temperatures of 275–523 K. It is demonstrated that the pressure increase causes a weaker temperature dependence of thermal conductivity. Processes are discussed which lead to additional scattering of heat waves in disordered media.     

Thermal conductivity of heptyl caproate at high temperatures and pressures

Measurements have been made on the thermal conductivity of heptyl caproate at 305–611 K and 0.098–98 MPa.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 57, No. 2, pp. 299–300, August, 1989.     

Thermal conductivity of various glass-reinforced plastics at temperatures below 80 K

The results of thermal conductivity measurements of glass-fabric base laminates CKTφ-5KT, CT0φ-1, CT0φ-HT and uniaxial glass-fibre base laminates 27–63C and AΓ-4C within the 4–80 K temperature range are presented. The thermal conductivities of CKTφ-5KT constituents have also been measured and the thermal conductivity in specific directions has been calculated. The technique used for calculation made it possible to find the thermal conductivities of the matrices of the glass-reinforced plastics under investigation. The effect of cooling heating cycles under vacuum on the thermal conductivity has also been studied.     

Thermal conductivity and heat capacity of liquid toluene at temperatures between 255 and 400 K and at pressures up to 1000 MPa

The thermal conductivity and heat capacity c _p of liquid toluene have been measured by the ac-heated wire method up to 1000 MPa in the temperature range from 255 to 400 K. The total error of thermal conductivity measurements is estimated to be about 1 %, and the precision 0.3 %. The heat capacity per unit volume, pc _p, obtained directly from the experiment is uncertain within 2 or 3%. The vs p isotherms are found to cross one another at approximately 700 MPa. The minima in the pressure (or volume) dependence of c_p of toluene are evident at all temperatures investigated.     

Thermal conductivity of nitrogen at high pressures

The results of the measurements of the thermal conductivity coefficients of nitrogen at 298.15 K from atmospheric pressure up to 1 GPa are reported. The experimental values are used to test the Modified Enskog Theory and the corresponding state principle. The experimental values are also compared with the results of computer simulation of the thermal conductivity of a Lennard Jones fluid.     

Thermal conductivity of polymethylphenylsiloxanes at high pressures

Results are presented of an experimental investigation of the thermal conductivity of polymethylphenylsiloxanes in the 20–200°C temperature range and up to 200-MN/m² pressure range. An equation is proposed to compute the heat conduction in the temperature and pressure ranges investigated.     

Thermal diffusivity, thermal conductivity, and specific heat of flax fiber–HDPE biocomposites at processing temperatures

There is increasing work on the use of flax fibers as reinforcement for manufacturing composites because of their lower cost and environmental benefit. During manufacturing of such natural fiber–plastic composites, heat transfer is involved, but information about the thermal conductivity and thermal diffusivity at the processing temperatures is not available. In this study, the thermal conductivity, thermal diffusivity, and specific heat of flax fiber–high density polyethylene (HDPE) biocomposites were determined in the temperature range of 170–200 °C. The fiber contents in biocomposites were 10%, 20%, and 30% by mass. Using the line-source technique, the instrumental setup was developed to measure the thermal conductivity of biocomposites. It was found that the thermal conductivity, thermal diffusivity, and specific heat decreased with increasing fiber content, but thermal conductivity and thermal diffusivity did not change significantly with temperature in the range studied. The specific heat of the biocomposites increased gradually with temperature.     

Thermal conductivity measurements at low temperatures

We describe briefly the experimental facilities developed for the measurement of thermal conductivity of solids in the temperature range 10K–300K. Different techniques have been used for the determination of thermal conductivity, depending on the relaxation time of the system under investigation. Measurements on stainless steel 304, using steady state and non-steady state methods are presented. Values of thermal conductivity obtained by both these methods agree to each other and are consistent with those reported earlier. Paper presented at the poster session of MRSI AGM VI, Kharagpur, 1995     

Thermal conductivity of mica at low temperatures

The thermal conductivity of muscovite and phlogopite has been measured over a temperature range of 3 to 320 K, in directions parallel and perpendicular to the cleavage planes. Both materials showed anisotropic behaviour. The room temperature values for muscovite and phlogopite, respectively, were 4.05 and 3.7 W m^–1 K^–1 for conductivity parallel to the planes, and 0.46 and 0.44 W m^–1 K^–1 perpendicular to the planes. Plots of the variation of thermal conductivity with temperature for both directions in the two materials show a gradual rise in conductivity as the temperature is lowered below room temperature. All four curves reach a peak at about the same temperature of 15 K. The peak values obtained were 12.4 and 7.25 W m^–1 K^–1 parallel to the planes, and 4.7 and 2.05 W m^–1 K^–1 perpendicular to the planes.On leave from Australian Broadcasting Commission.     

Thermal conductivity of methane-ethane mixtures at temperatures between 140 and 330 K and at pressures up to 70 MPa

The paper presents new measurements on the thermal conductivity of three methane-ethane mixtures with methane mole fractions of 0.69, 0.50, and 0.35. The thermal conductivity surface for each mixture is defined by up to 13 isotherms at temperatures between 140 and 330 K with pressures up to 70 MPa and densities up to 25 mol · L^–1. The measurements were made with a transient hot-wire apparatus. They cover a wide range of physical states including the dilute gas, the single-phase fluid at temperatures above the maxcondentherm, the compressed liquid states, and the vapor at temperatures below the maxcondentherm. The results show an enhancement in the thermal conductivity in the single-phase fluid down to the maxcondentherm temperature, as well as in the vapor and in the compressed liquid. A curve fit of the thermal conductivity surface is developed separately for each mixture.Paper presented at the Ninth Symposium on Thermophysical Properties, June 24–27, 1985, Boulder, Colorado, U.S.A.     

Thermal conductivity of inert gases at low temperatures

An experimental and theoretical study of the thermal conductivity of helium, argon, and xenon is reported. The experimental apparatus is described, and the results are discussed.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 30, No. 4, pp. 671–679, April, 1976.     

Thermal conductivity of polyethyl siloxane liquids at high pressures

The thermal conductivities of three polyethyl siloxane liquids have been investigated experimentally at pressures up to 200 mN/m² in the temperature interval from 20 to 200°C. Equations are proposed for calculations.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 33, No. 3, pp. 464–466, September, 1977.     

Density of isoamyl and heptyl alcohols at various temperatures and pressures

The hydrostatic weighing method is used to determine the density of isoamyl alcohol at T=273.15-587.37°K and the density of heptyl alcohol at T=273.15–575.07°K at pressures of 10.86–491.4 bar. An equation of state is presented.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 40, No. 2, pp. 313–318, February, 1981.     

Dynamic viscosities of n-butyraldehyde and isobutyraldehyde at various temperatures and pressures

New experimental data are presented on the dynamic viscosity of n-butyraldehyde and isobutyraldehyde at 293.53–501.88°K and 0.1–49.1 MPa.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 40, No. 6, pp. 1033–1034, June, 1981.     

Investigation of thermal conductivity of liquid formates at high temperatures and pressures

Experimental data on the thermal conductivity of butyl formate and octyl formate in a wide range of temperatures and pressures are given.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 37, No. 2, pp. 324–328, August, 1979.     

Thermal conductivity of ceramic fibrous insulators at high temperatures

The temperature and bulk density dependence of the thermal conductivity of commercial aluminosilicate fibrous insulators were studied by using the transient hot wire method. The thermal conductivity of ceramic fibrous insulators in both air and helium gas atmosphere increased with increasing bulk density. At high temperatures, however, the insulators with lower bulk density showed a higher thermal conductivity because of heat radiation. The following experimental relation between thermal conductivity and temperature was obtained for aluminosilicate fibruous insulators: =a exp(b). Relationships are given between the constants a and b and the bulk density. From the relation, the optimum bulk density of ceramic fibrous insulators can be calculated for each working temperature.Paper presented at the Fourth Japan Symposium on Thermophysical Properties, October 20–22, 1983, Yokohama, Japan.     

Thermal conductivity of superconducting UPt3 at low temperatures

We study the thermal conductivity within the E_1g and E_2u models for superconductivity in UPt₃ and compare the theoretical results for electronic heat transport with recently measured results reported by Lussier, Ellman and Taillefer. The existing data down to T/T_c 0.1 provides convincing evidence for the presence of both line and point nodes in the gap, but the data can be accounted for either by an E_1g or E_2u order parameter. We discuss the features of the pairing symmetry, Fermi surface, and excitation spectrum that are reflected in the thermal conductivity at very low temperatures. Significant differences between the E_1g and E_2u models are predicted to develop at excitation energies below the bandwidth of the impurity-induced Andreev bound states. The zero-temperature limit of the axis thermal conductivity, lim_T0 k_c/T, isuniversal for the E_2u model, but non-universal for the E_1g model. Thus, impurity concentration studies at very low temperatures should differentiate between the nodal structures of the E_2u and E_1g models.     

Methods for measurement of thermal conductivity and specific heat at moderate,low, and cryogenic temperatures

Physical principles and schematic diagrams of automated devices for measurement of thermophysical properties of materials and components in the temperature range 100–700 K are presented.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 53, No. 6, pp. 987–994, December, 1987.