			Home About us Contact

Transfer Behaviour (transfer + behaviour)

Distribution by Scientific Domains

Engineering	50%

Selected Abstracts

Free Convective Mass Transfer Behaviour of Inclined Cylinders with Active Ends

THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2003
Inderjit Nirdosh
Abstract Rates of mass transfer at inclined cylinders with active ends were determined under natural convection conditions by measuring the limiting current of copper deposition from acidified copper sulphate. Physical properties of the solution, cylinder dimensions and inclination were varied to produce a ScGr range of 1.53 × 109 to 7 × 1010. Under these conditions the data for different orientations were correlated by Sh = 1.075 (ScGr)0.242. The characteristic length used in obtaining Sh and Gr was calculated by dividing the cylinder surface area by the cylinder perimeter projected onto the horizontal plane. At high CuSO4 concentrations a reasonable agreement was found between the experimental rate of mass transfer and that calculated by summing the rate of mass transfer at individual surfaces of the cylinder. Deviations were observed at low CuSO4 concentrations, and the possible causes of the deviations were explained. On a déterminé les taux de transfert de matière dans le cas de cylindres inclinés aux extrémités actives dans des conditions de convection naturelle, en mesurant le courant limite du dépôt de cuivre venant de sulfate de cuivre acidifié. On a fait varier les propriétés physiques de la solution, les dimensions de cylindre et l'inclinaison pour donner une gamme de ScGr de 1.53 × 109 to 7 × 1010. Dans ces conditions, les données pour différentes orientations ont été corrélées par Sh = 1.075 (ScGr)0.242. La longueur caractéristique utilisée pour obtenir Sh et Gr a été calculée en divisant la superficie du cylindre par le périmètre projeté sur un plan horizontal. À de fortes concentrations de CuSO4, un accord raisonnable est trouvé entre le taux de transfert de matière expérimental et celui qui est obtenu en faisant la somme des taux de transfert de matière sur les différentes surfaces du cylindre. Des écarts sont observés à de faibles concentrations de CuSO4, et les causes possibles de ces écarts sont expliquées. [source]

Heat Transfer in Polypropylene-Based Foams Produced Using Different Foaming Processes,

ADVANCED ENGINEERING MATERIALS, Issue 10 2009
Marcelo Antunes
This paper presents the characterization of the cellular structure and thermal conduction behaviour of polypropylene foams produced using different foaming processes, with the aim of selecting the best possible PP foam thermal insulator. Thermal conductivity results have shown that the global heat transfer behaviour is controlled by the relative density. For relative densities higher than 0.2, thermal conductivity differences were insignificant, the data being predicted by the mixture's rule and Russell's model. In the low density range, all of the proposed models underestimated the overall conductivity, the effect of the processing method being more significant, slight differences being observed between foams produced by extrusion and those produced by gas dissolution with higher cell sizes and anisotropies. Foams with finer cellular structures showed to be better insulating materials. [source]

An integrated, finite element-based process model for the analysis of flow, heat transfer, and solidification in a continuous slab caster

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 3 2003
C. H. Moon
Abstract An integrated, finite element-based process model is presented for the prediction of full three-dimensional flow, heat transfer, and solidification occurring in a continuous caster. Described in detail are the basic models for the analysis of turbulent flow and heat transfer in the liquid steel zone, in the zone of mixture of the liquid steel and solidified steel, and in the solidified zone. Then, the models are integrated to form a process model which can take into account the strong interdependence between the heat transfer behaviour and the flow behaviour. The capability of the process model to reveal the detailed aspects of turbulent flow, heat transfer, and solidification occurring in a continuous caster is demonstrated through a series of process simulations. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Large-scale specimen testing on friction and wear of pure and internally lubricated cast polyamides

LUBRICATION SCIENCE, Issue 3 2006
Pieter SamynArticle first published online: 4 JUL 200
Abstract Due to the casting process for nylons, their composition can easily be modified to cover a wide range of mechanical properties and applications, especially as large wear surfaces in, for example, crane guidances. Presently, selection tests for working conditions up to 40MPa are presented on pure Na-catalysed polyamides, oil-filled polyamides with homogeneous oil dispersions and holes in the surface containing oil lubricant and two types of thermoplastic solid-lubricated polyamides. Pure polyamides are, however, prone to high and unstable sliding at pressures as low as 10MPa with brittle fracture and lumpy transfer. Oil lubrication is not able to remove the sliding instabilities as oil supply to the sliding interface is controlled by migration effects that are restricted by deformation and thermal softening or melting of the polyamide matrix. Although friction and wear are lower and more stable for samples with oil supplied through lubricating holes, additional running-in phenomena are attributed to a relatively thick transfer film that is brittle and easily peels off. A continuous thick molten film or island-like deposition occurs on the polyamide surface. Solid lubricants are able to stabilize friction and lower wear down to the formation of a thin and coherent transfer film. However, increasing the amount of lubricants induces lower mechanical properties and higher deformation of the test samples. The differences in transfer behaviour are discussed with reference to optical microscopy and calculations of bulk and flash temperatures. Copyright © 2006 John Wiley & Sons, Ltd. [source]