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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

CHARACTERIZATION AND SCALING OF ENHANCED HEAT TRANSFER IN HEAT SINK CHANNELS USING INTEGRATED AEROELASTICALLY FLUTTERING REED

Get access (open in a dialog) DOI: 10.1615/IHTC16.cov.023653
pages 3151-3158

Résumé

Low Reynolds (Re) number forced convection heat transport within high aspect ratio, rectangular mm-scale channels of air cooled heat exchangers where pressure losses are reduced by low flow rates is enhanced by deliberate formation of unsteady, small-scale vortical motions. These vortical motions which substantially increase the local heat transfer coefficient at the fins' surfaces, and the mixing between the surface thermal boundary layers and the cooler core flow are induced by the interactions between autonomous, aeroelastically fluttering cantilevered thin-film reeds and the channel flow. Such improved thermal performance can yield further reduction in the required air volume flow rate for a given heat flux and surface temperature and thereby the air-side pressure losses. This approach to thermal performance enhancement is investigated in a mm-scale, modular model of the rectangular heated fin channels with emphasis on the increases in local and global Nusselt number (Nu) and the associated fluid power over a range of flow rates and varying channel heights. It is shown that the reed flutter increases the turbulent kinetic energy of the flow even when the base flow undergoes transition to turbulence and thereby leads to a relative increase in the global Nu that increases with Re. It is also demonstrated that the global heat transfer characteristics of the channel with and without the reed scale with the channel height through transition.