Showing papers by "Marc J. Assael published in 1989"

Absolute measurements of the thermal conductivity of mixtures of alkene-glycols with water

Abstract: New absolute measurements of the thermal conductivity of mixtures of methanol, ethanol, and propanol with water are presented. The measurements were performed in a tantalum-type transient hot-wire instrument at atmospheric pressure, in the temperature range 300–345 K. The overall uncertainty of the reported values is estimated to be less than ±0.5%, an estimate confirmed by measurements of the thermal conductivity of water. The mixtures with water studied have compositions of 25. 50, and 75%, by weight, of methanol and ethanol and 50%, by weight, of propanol. A recently proposed semiempirical scheme for the prediction of the thermal conductivity of pure liquids is extended to allow the prediction of the thermal conductivity of these mixtures from the pure components, as a function of both composition and temperature.

Thermal conductivity of liquids: Prediction based on a group-contribution scheme

Abstract: A new semiempirical predictive scheme for the thermal conductivity of liquids, based on an extension of concepts derived from the rigid-sphere model of dense-fluid transport properties, is presented The scheme makes use of the idea of group contributions to the molecular volume and is developed with the aid of accurate thermal conductivity data for the alkanes, the aromatic hydrocarbons, the alcohols, and the diols, along the saturation line and at elevated pressures The procedure has been tested against other thermal conductivity data, not included in its formulation, and has been found to predict values within ±4% of the experimental data in the temperature range 110–370 K for pressures up to 600 MPa

Absolute Measurements of the Thermal Conductivity of Some Aqueous Chloride Salt Solutions

Abstract: New absolute measurements of the thermal conductivity of aqueous NaCl, KCl and CaCl2 solutions are presented. The concentrations studied were 10% and 20% by weight of NaCl and KCl, and 10, 20 and 30% by weight of CaCl2. The measurements were performed in a transient hot-wire apparatus employing two thin tantalum wires coated with an anodic tantalum pentoxide insulation layer. The temperature range examined was 290 to 345 K and the pressure was atmospheric. The uncertainty of the measurements is estimated to be ±0.5%, an estimate confirmed by the measurement of the thermal conductivity of water. — Existing correlations for the thermal conductivity of aqueous inorganic salt solutions are also examined. The measurements have been used to develop a simple consistent correlative and predictive scheme that allows the correlation of the thermal conductivity of these solutions with an uncertainty of ±0.7% and the prediction of the thermal conductivity to high pressures with an uncertainty of ±2.5%.