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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 EXPERIMENTAL INVESTIGATION OF FORCED CONVECTION BETWEEN CONCENTRIC SPHERES AT LOW REYNOLDS NUMBER

Get access (open in a dialog) DOI: 10.1615/IHTC6.980
pages 179-184

Sinopsis

An experimental investigation of forced convection between concentric spheres has been performed. With air as the fluid, flow was vertically downward, entering at the north pole and exiting at the south pole. Data were obtained for an outer sphere having a diameter of 27.2 cm, with four inner spheres yielding annular gaps of .38 cm, 1.27 cm, 1.51 cm and 3.58 cm diameter. Reynolds numbers were varied from 103 to 2.5 × 1044. Inner and outer spheres were maintained at constant temperatures with the inner sphere heated and the outer sphere cooled.
Temperature and velocity profiles were measured at several angular positions. Mean heat-transfer coefficients were determined knowing inner and outer sphere temperatures, bulk fluid temperatures and energy supplied to the inner sphere. Heat transfer was correlated in terms of Reynolds number of the flow and radius ratio. Nusselt numbers agreed well with a recently published numerical analysis of the problem. Temperature measurements indicated local heat transfer coefficients were influenced by inlet flow conditions. Extrapolation of the correlation equation to the case of isolated spheres showed good agreement with published results for single isolated spheres.