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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

INFLUENCE OF A PERIODICALLY RECIRCULATING FLOW ON CONVECTIVE UNSTEADY HEAT TRANSFER

Get access (open in a dialog) DOI: 10.1615/IHTC8.1990
pages 1005-1010

要約

Previous experimental studies dealing with convection in unsteady ducted flows have shown that, if compared to steady flows, some changes on heat transfer rates can be obtained under certain circumstances related to the flow parameters. In the present communication, we briefly present the conditions of an experimental work where important local increases in heat transfer between the wall and the fluid flow occur. Those increases have been obtained for turbulent flows in a circular duct where their axial pressure gradient is described as a perio-dical modulation with time. The dynamic fluid field has been investigated by means of split-film probes and the existence of a reverse flow during a fraction of the modulation period has been shown. The behaviour of the coupling between main flow and reverse flow can be identified to an oscillatory shear flow. The theoretical developments given by KAIPING's analysis about the influence of recirculations on heat transfer have been checked by the use of wall-mounted flux-metering probes with short response.