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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

LOCAL HEAT TRANSFER MEASUREMENTS IN AN AXISYMMETRIC CAVITY WITH TURBULENT FLOW

Get access (open in a dialog) DOI: 10.1615/IHTC8.530
pages 1071-1076

摘要

The local heat transfer coefficients in an axisymmetric cavity in a circular tube with a constant wall temperature have been measured for turbulent air flow. This interesting geometry (an abrupt expansion followed by an abrupt contraction) produces a separated recirculating flow with highly nonuniform heat transfer coefficients in the cavity. The flow just upstream of the expansion into the cavity was unheated and proved to be fully-developed hydrodynamically.
The measurements have been performed for the downstream (cavity) Reynolds number of 17,730 (upstream Reynolds number of 44,325) and a cavity expansion/contraction ratio of 0.4 with a broad range of cavity lengths (up to 10 step heights). The results are compared with the abrupt expansion case (i.e., infinite length of cavity).
The results show a dramatic increase in the local heat transfer coefficients as the downstream end of the cavity is approached. They also show an interesting minimum in the Nusselt number near the upstream cavity face for the cavity lengths of 8.25 and 10 step heights, suggesting the possible existence of a secondary recirculating region very close to the upstream cavity corner for longer cavities.