Characterization and optimization of the thermal performance of miniature piezoelectric fans

Piezoelectric fans have emerged as a viable cooling technology for the thermal management of electronic devices, owing to their lowpower consumption, minimal noise emission, and small and configurable dimensions. Piezoelectric fans are investigated for application in the cooling of low-power electronics. Different experimental configurations are considered, and the effect of varying the fan amplitude, the distance between the fan and the heat source, the fan length, its frequency offset from resonance, and the fan offset from the center of the heat source are studied to assess the cooling potential of the fans. A design of experiments (DOE) analysis revealed the fan frequency offset from resonance and the fan amplitude as the critical parameters. Transfer functions are obtained from the DOE analysis for the implementation of these fans in electronics cooling. For the best case, an enhancement in convective heat transfer coefficient exceeding 375% relative to natural convection was observed, resulting in a temperature drop at the heat source of more than 36.4 degrees C. A computational model for the flow field and heat transfer induced by the piezoelectric fan is also developed. Effects of the flow on convection heat transfer for different fan-to-heat source distances and boundary conditions are analyzed. Transition between distinct convection patterns is observed with changes in the parameters. The computational results are validated against experimental measurements, with good agreement. (c) 2006 Elsevier Inc. All rights reserved.