| Summary: | 碩士 === 國立臺灣科技大學 === 工程技術研究所 === 81 === The heat transfer and pressure drop characteristics of an array
of offset-strip fins, aligned parallel to the direction of a
forced convection air flow in a rectangular, straight duct,
have been investigated experimentally in the range of Reynolds
numbers between 650 and 33000. The aim of this work is to
identify the important parameters and provide guidelines for
designers of heat transfer surfaces and workers attempting to
correlate experimental data. The periodic interruptions
preclude the attainment of hydrodynamic and thermal development
of the type that is encountered in conventional continuous
plate fin duct flow, but a periodic fully developed regime can
exist. During the course of the experiments, the thickness and
length of the fins in the array were varied parameterically.
The result of these measurements are reported and comparisons
are made with published data on similar surfaces. The heat
transfer and pressure drop performances of the fin arrays are
confirmed to be little affected by the fin thickness in the low
Reynolds number range, as previously suggested from numerical
study. However, in the middle and high Reynolds number range,
the fin arrays heat transfer performance is demonstrated to be
enhanced noticably by the ratio of thickness to length of the
fin. This is related to the flow instability occuring in the
wake of a fin on the upstream side.
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