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ISSN Online: 2377-424X

ISBN Print: 0-89116-559-2

International Heat Transfer Conference 8
August, 17-22, 1986, San Francisco, USA

TURBULENT HEAT TRANSFER TO THE FLOW IN A CONCENTRIC ANNULUS WITH A ROTATING INNER CYLINDER

Get access (open in a dialog) DOI: 10.1615/IHTC8.1810
pages 895-900

Sinopsis

Experimental and theoritical studies have been conducted to investigate the effects of the swirl on the heat and momentum transfer in a concentric annulus with a rotating inner cylinder, where the flow field is unstable due to the centrifugal force. Experiments indicate that the Nu number together with the wall friction factor increases with increasing the rotating speed. In order to study the causes of the phenomena, in the first place, flow patterns are visualized. The flow visualizations indicate the extensive fluid mixing in radial direction is induced due to swirl. In the second place, measurements of time-mean velocities and the turbulence properties were made by using a two-color laser Doppler velocimeter to detect two velocities (axial and tangential velocity) components simultaneously. It was observed that axial velocity profile becomes flattened and turbulent intensities increase due to swirl. These results seem to explain the causes of the increase of the Nu number and the friction factor due to swirl. Computations on the flow and heat transfer applying k−ε two equations turbulent model are compared with the experimental results. The effects of the swirl on the flow and heat transfer can be qualitatively predicted by the computations.