Abstract
Direct impinging synthetic jets are a proven method for heat transfer enhancement, and have been subject to extensive research. However, despite the vast amount of research into direct synthetic jet impingement, there has been little research investigating the effects of a synthetic jet emanating from a heated surface, this forms the basis of the current research investigation. Both single and multiple orifices are integrated into a planar heat sink forming a synthetic jet, thus allowing the heat transfer enhancement and flow structures to be assessed. The heat transfer analysis highlighted that the multiple orifice synthetic jet resulted in the greatest heat transfer enhancements. The flow structures responsible for these enhancements were identified using a combination of flow visualisation, thermal imaging and thermal boundary layer analysis. The flow structure analysis identified that the synthetic jets decreased the thermal boundary layer thickness resulting in a more effective convective heat transfer process. Flow visualisation revealed entrainment of local air adjacent to the heated surface; this occurred from vortex roll-up at the surface of the heat sink and from the highly sheared jet flow. Furthermore, a secondary entrainment was identified which created a surface impingement effect. It is proposed that all three flow features enhance the heat transfer characteristics of the system.
Highlights
IntroductionHeat dissipation in microprocessors has more than doubled [1]
Over the past decade, heat dissipation in microprocessors has more than doubled [1]
The results indicate that increasing the frequency of actuation, increases the rate of heat transfer in general
Summary
Heat dissipation in microprocessors has more than doubled [1]. The trend of electronic device miniaturization and increasing power density results in very high localised heat fluxes, this presents a thermal bottleneck in the electronics component cooling sector [2]. The basic requirement for a thermal management system is to efficiently dissipate heat from a heated surface to ensure safe operating conditions, as thermal overstressing is one of the major causes for failure of electronic devices [3]. As form factors of electronic devices decrease in size, there is an increase in the demand for confined space thermal management solutions. Synthetic jets have been at the forefront of electronic component cooling research for the past number of years. The strength and size of the vortex ejected from the synthetic jet cavity is determined by the dimensionless stroke length, L0/D, where the stroke length L0 is determined by the following expression:
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
