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ISSN Online: 2377-424X

ISBN Print: 0-85295-345-3

International Heat Transfer Conference 10
August, 14-18, 1994, Brighton, UK

INFLUENCE OF A SPHERICAL INCLUSION ON THE THERMAL CONDUCTIVITY OF A ROD: AN EXPERIMENTAL STUDY

Get access (open in a dialog) DOI: 10.1615/IHTC10.760
pages 355-359

Abstract

The thermal conductivity of a composite cylindrical element which contains a spherical inclusion (or cavity) on its axis at the mid-point of its length was found analytically by representing the solution of the Laplace equation in the various regions in series form and appropriately matching at the interfaces. The lateral surface of the cylinder was taken to be insulated; the temperatures on each of the bases are uniform, differing by some given value. The details of this solution are given in Shai et al (1993). A series solution was found for spheres (or cavities) which is stable for diameters up to 90% of that of the cylinder for the entire range of conductivity ratios.
An experimental set-up has been built to verify the analytical series solution. Cylindrical specimens of 60 mm diameter and 120 mm length were used; the lateral surfaces are insulated; a uniform heat source is provided at one base, a sink at the opposite base. The cylinders themselves are made of aluminum; the inclusions (cavities) are air at atmospheric pressure. A range of cavity diameters has been used. Heat transfer rates determined from the experiments agree well with the theoretical calculations.