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ISSN Online: 2377-424X

ISBN Print: 0-89116-130-9

International Heat Transfer Conference 6
August, 7-11, 1978, Toronto, Canada

AN INTERFEROMETRIC STUDY OF THE LOCAL HEAT TRANSFER BY NATURAL CONVECTION IN INCLINED AIRFILLED ENCLOSURES

Get access (open in a dialog) DOI: 10.1615/IHTC6.3320
pages 287-292

Resumo

A number of relations for the natural convective heat transfer in inclined airfilled enclosures are known. However there is some discrepancy between these relations with respect to the angle dependence and the Ra dependence. Furthermore there is little insight in the contribution of the side wall regions to the heat transfer. Measurements of the local heat transfer are hardly available. In this investigation we measured the local heat transfer using a holographic interferometer. An enclosure with isotherm hot and cold walls and adiabatic side walls was used. The air layer was heated from below. Ra was varied from 104−4.106 and the angle of inclination from 0°−90°. By integrating Nux along the hot plate Nu was computed. The inacuracy in Nux is 5% and in Nu 2%. From our experiments it appeared that for ø>40° Nux shows a maximum at the lower side of the hot plate and a minimum at the upper side of the hot plate. This maximum decreases with decreasing Ñ„ while the minimum increases with decreasing ø. For ø<30° Nux shows several maxima and minima along the hot plate. The resulting Nu increases with decreasing ø. At low Ra number Nu is in good agreement with literature. At high Ra number there is some deviation with literature. Nu-Ra relations are given for different angle of inclination, valid for 105 < Ra <4.106.