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ISSN Online: 2377-424X

International Heat Transfer Conference 12
August, 18-23, 2002, Grenoble, France

Heat Transfer Control from a Plate by Parallel Synthetic Impinging Jets

Get access (open in a dialog) DOI: 10.1615/IHTC12.2970
6 pages

Sinopsis

The control of scalar transport associated with turbulent shear flows is desired in many thermal engineering applications. Above all, heat transfer control by impinging jets is important due to their extensive uses. Previous works of such attempts were limited to control of time-averaged quantities via active or passive technique. An experimental study has been performed to investigate the effect of excitation on the local heat transfer distributions in time- and space-domain from a plate to parallel planar impinging twin jets. The excitation method used in the current investigation, called synthetic excitation, was achieved by manipulating the local shear layers through fine slits at the nozzle exit with phase lag, four excitation patterns and various phase setting. The excitation configuration included full excitation mode, single-sided excitation mode, outer excitation mode, and inner excitation mode. The results showed synthetic excitation was effective on controlling the local heat transfer, that is, the profiles of local heat transfer coefficients could be controlled by excitation in timeaveraged and space-domain. Phase lag during excitations was influential especially for small nozzle-to-plate distance. An attempt to control the local heat transfer in the time-domain was conducted so that such control could be possible over a longer time-scale.