Abonnement à la biblothèque: Guest

ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Vortex Heat Transfer Enhancement in Dimpled Channels

Get access (open in a dialog) DOI: 10.1615/IHTC15.hte.009952
pages 4355-4367

Résumé

There are many passive techniques of heat transfer enhancement ranging from surface (2D) to volumetric (3D) vortex generators and turbulizing elements, however only a few of them are capable to provide a reliable increase in a heat transfer rate without significant increase in pressure losses. One of such successful techniques is the profiling of a heat transfer surface with the periodical arrangement of 3D cavities (dimples). The authors explored that the deviation of the dimple geometry from the spherical shape affects the flow structure as well as thermal and hydraulic performance of the dimpled wall. Detailed numerical simulation of fluid flow and heat transfer was performed in the narrow channel with the 2.5 × 0.33 cross section normalized by the equivalent dimple footprint diameter at the Reynolds number Re=10,000-100,000 and the constant heat flux through the dimpled wall. The dimple geometry was varied by changing the aspect ratio of the dimple footprint from 1 to 4.5 keeping the same dimple footprint area. In the course of the numerical simulation study, the optimal geometry, the arrangement, and the orientation of oval dimples on the heated surface are established to achieve the superior thermal and hydraulic performance of the dimpled surface. Numerical simulation results of local and integral heat transfer characteristics enhanced due to dimples as vortex generators clearly illustrated the flow restructuring and the increase in the thermal and hydraulic performance.