Enhancement of piezoelectric fan cooling by geometrical arrangements

Piezoelectric fan cooling is drawing growing attention for its compact size and high energy efficiency. However, its cooling capacity is not good enough and needs to be maximized to catch up with the in-dustry demand. In this work, we aim to increase heat transfer performance by varying piezoelectric fan locations and channel configurations. The effect of fan location is firstly studied. By tuning the fan posi-tion, a higher streamwise velocity is achieved, thus increasing the heat transfer. A fan inserted into the channel achieves a 55% enhancement on the Nusselt number compared with natural convection. On top of this, the effect of the channel configuration is explored. Both expansion and contraction configurations benefit heat transfer, and the optimal one adds a further 10% enhancement on top of the parallel config-uration case. That is, the maximum cooling enhancement is 70% compared with natural convection. The fan motion is captured by a high-speed camera. Flow visualization is used to investigate the flow pattern. The channel streamwise fluid velocity is examined. It is found that the contraction configuration boosts the streamwise velocity and generates a jet flow pattern at the channel outlet. The expansion configura-tion significantly alters the flow motion with more vortices in a longer transmission distance, yielding a stronger spanwise mixing. The findings demonstrate that geometrical arrangements can substantially en-hance the heat transfer performance of the piezoelectric fan, thus paving the way for tackling the urgent cooling requirement.(c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

Piezoelectric fan cooling is receiving increased attention for its compact size and high energy efficiency. This study investigates the impact of fan location and channel configuration on heat transfer performance. By adjusting the fan position, a higher streamwise velocity is achieved, leading to improved heat transfer. Inserting a fan into the channel results in a 55% enhancement of the Nusselt number compared to natural convection. Additionally, both expansion and contraction configurations enhance heat transfer, with the optimal configuration providing an additional 10% enhancement. Flow visualization and velocity measurements reveal that the contraction configuration boosts streamwise velocity and generates a jet flow pattern, while the expansion configuration promotes more vortices and spanwise mixing.