It is shown that a “nanofluid” consisting of copper nanometer-sized particles dispersed in ethylene glycol has a much higher effective thermal conductivity than either pure ethylene glycol or ethylene glycol containing the same volume fraction of dispersed oxide nanoparticles. The effective thermal conductivity of ethylene glycol is shown to be increased by up to 40% for a nanofluid consisting of ethylene glycol containing approximately 0.3 vol % Cu nanoparticles of mean diameter <10 nm. The results are anomalous based on previous theoretical calculations that had predicted a strong effect of particle shape on effective nanofluid thermal conductivity, but no effect of either particle size or particle thermal conductivity.

Anomalously increased effective thermal conductivities of ethylene glycol-based nanofluids containing copper nanoparticles

Oxide nanofluids were produced and their thermal conductivities were measured by a transient hot-wire method. The experimental results show that these nanofluids, containing a small amount of nanoparticles, have substantially higher thermal conductivities than the same liquids without nanoparticles. Comparisons between experiments and the Hamilton and Crosser model show that the model can predict the thermal conductivity of nanofluids containing large agglomerated Al{sub 2}O{sub 3} particles. However, the model appears to be inadequate for nanofluids containing CuO particles. This suggests that not only particle shape but size is considered to be dominant in enhancing the thermal conductivity of nanofluids.

Measuring Thermal Conductivity of Fluids Containing Oxide Nanoparticles

We have produced nanotube-in-oil suspensions and measured their effective thermal conductivity. The measured thermal conductivity is anomalously greater than theoretical predictions and is nonlinear with nanotube loadings. The anomalous phenomena show the fundamental limits of conventional heat conduction models for solid/liquid suspensions. We have suggested physical concepts for understanding the anomalous thermal behavior of nanotube suspensions. In comparison with other nanostructured materials dispersed in fluids, the nanotubes provide the highest thermal conductivity enhancement, opening the door to a wide range of nanotube applications.

Anomalous thermal conductivity enhancement in nanotube suspensions

Heat transfer characteristics of nanofluids: a review

Pore fluids strongly influence the seismic properties of rocks. The densities, bulk moduli, velocities, and viscosities of common pore fluids are usually oversimplified in geophysics. We use a combination of thermodynamic relationships, empirical trends, and new and published data to examine the effects of pressure, temperature, and composition on these important seismic properties of hydrocarbon gases and oils and of brines. Estimates of in-situ conditions and pore fluid composition yield more accurate values of these fluid properties than are typically assumed. Simplified expressions are developed to facilitate the use of realistic fluid properties in rock models. Pore fluids have properties that vary substantially, but systematically, with composition, pressure, and temperature. Gas and oil density and modulus, as well as oil viscosity, increase with molecular weight and pressure, and decrease with temperature. Gas viscosity has a similar behavior, except at higher temperatures and lower pressures, where the viscosity will increase slightly with increasing temperature. Large amounts of gas can go into solution in lighter oils and substantially lower the modulus and viscosity. Brine modulus, density, and viscosities increase with increasing salt content and pressure. Brine is peculiar because the modulus reaches a maximum at a temperature from 40 to 80°C. Far less gas can be absorbed by brines than by light oils. As a result, gas in solution in oils can drive their modulus so far below that of brines that seismic reflection bright spots may develop from the interface between oil saturated and brine saturated rocks.

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Seismic properties of pore fluids

This paper presents new experimental data for the viscosity of binary mixtures of xenon with the remaining monatomic gases, helium, neon, argon, and krypton. The measurements have been performed in a high precision oscillating-disk viscometer at atmospheric pressure and within the temperature range 25–500°C. The data have an estimated uncertainty of ±0.1% at 25°C increasing to ±0.3% at 500°C. The collision integrals for the interactions of xenon with the other monatomic species conform to the extended law of corresponding states formulated by Kestin, Ro and Wakeham. For each binary interaction the scaling parameters σij and ∈ij have been obtained. The ensemble of experimental results can be correlated by means of the appropriate kinetic theory expressions reinforced by the extended law of corresponding states. The deviations do not exceed 0.5%. The binary diffusion coefficients were calculated from the measured mixture viscosity and compared with the available experimental results. The standard deviation was estimated as ±2% which is within the mutual uncertainty of the two sets.

The viscosity and diffusion coefficients of the binary mixtures of xenon with the other noble gases

New experimental data on the viscosity of aqueous KCl solutions are reported. The data cover the temperature range 25 to 150/sup 0/C, the pressure range 0 to 30 MPa, and the concentration range 0 to 4.4 m. The experimental values have an estimated accuracy of +-1% over the entire range of pressure, temperature, and concentration. The viscosity has been correlated as a function of pressure, temperature, and concentration. The paper also provides a correlation for the density of KCl solutions in terms of pressure, temperature, and concentration. 15 figures, 10 tables.

Viscosity of aqueous potassium chloride solutions in the temperature range 25-150 .degree.C and the pressure range 0-30 MPa

The viscosity of argon-helium mixtures

This paper presents new measurements of the viscosity of the binary mixtures N2–Ar and N2–Kr both at zero density and in the temperature range 25–500°C. The measurements are compared with extensive calculations based on the extended law of corresponding states proposed by Kestin, Ro, and Wakeham. It is found that the calculations represent all data with a standard deviation of 0.33% and a maximum deviation of less than 0.5%. This is taken as new and additional evidence for the validity of the law of corresponding states. The latter is used as a device for the interpolation and extrapolation of the data in the form of tables ranging from 0°C to 2000°C for the mole fractions 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0 for each system.

Viscosity of the Binary Gaseous Mixtures of Nitrogen with Argon and Krypton

This paper reports relative measurements of the viscosity of three binary mixtures: Ne–N2, He–CO2, N2–Ar. Measurements were made at 20° and 30°C at pressures from 1–25 atm.

Joseph Kestin

Papers

The viscosity and diffusion coefficients of the binary mixtures of xenon with the other noble gases

Viscosity of aqueous potassium chloride solutions in the temperature range 25-150 .degree.C and the pressure range 0-30 MPa

The viscosity of argon-helium mixtures

Viscosity of the Binary Gaseous Mixtures of Nitrogen with Argon and Krypton

Viscosity of Three Binary Gaseous Mixtures