Enhancement of channel-flow convection heat transfer using piezoelectric fans

Abstract

This paper presents the experimental and numerical studies on the convection heat transfer enhancement of air channel flow using a piezoelectric fan. Significant improvements in channel convection heat transfer are observed experimentally by operating the piezoelectric fan at 90.3 Hz under various channel flow velocities. The peak-to-peak displacement of the piezoelectric fan increases up to 11.8 mm, which covers 53% of the channel width. The piezoelectric fan is tested at three different relative locations from a heated surface in the channel. As a result, the piezoelectric fan, aligned at the front-end of the heated surface, achieves a maximum heat transfer enhancement of 102% at the channel Reynolds number of 603. The numerical study is performed using ANSYS Fluent to investigate complex flow fields created by the piezoelectric fan and their impact on the thermal responses of the heated surface in the channel. The Q-criterion analysis is used to identify vortical structures generated from the piezoelectric fan and understand their transport characteristics. It is found that the formation, propagation, and impinging dynamics of vortical structures are the significant factors that affect the convective heat transfer rate of the heated surface in the channel.