On the Heat Transfer Characteristics of Highly Compact Heat Sinks

Abstract

This study conducts an experimental study concerning the airside performance of highly compact heat sinks under cross flow condition. The test fin patterns can be classified into four categories, namely the base plain fin heat sink (Type I), interrupted fin geometry (Type II), dense vortex generator (Type III), loose vortex generator (Type IV) and their combinations. It is found that the heat transfer performance is strongly related to the arrangement of enhancements. The interrupted and dense vortex generator configurations normally contribute more pressure drop penalty than improvements of heat transfer. This deterioration becomes especially evident at a lower frontal velocity. The oblique VG with cannelure structure shows an appreciable lower pressure drop than that of plain fin geometry. In the meantime, the presence of interrupted surface may also jeopardize heat conduction path due to constriction. The results indicate that the vortex generators operated at a higher frontal velocity is more beneficial than that of plain fin geometry. In summary of the test results, it is therefore concluded that augmentation via various fin patterns like interrupted or vortex generator is quite effective only at developing region. However, the conventional enhanced fin patterns lose its superiority at the fully developed region. To tackle this problem, some techniques employing swing flow or unstable flow field accompanied with the asymmetric design, shows potential to resolve this problem.