Thermal and Acoustics Investigation of a Combined Porous Media – Piezoelectric Fan System

This paper investigates the heat transfer and noise attenuation characteristics of a system that integrates the piezoelectric fan, porous heat sink, and a rotary fan. For the present study, the piezoelectric fan is placed inside a single corrugated porous structure and is oscillated in the presence of mean flow. The piezoelectric fan is operated at its first resonance frequency to get the highest tip displacement. The experiments are performed at different rotary fan flow rates, and the effect of piezoelectric fan agitation for heat transfer enhancement is tested. There is a maximum of 9.47% improvement in thermal resistance due to piezoelectric fan agitation in the porous structure. It is observed that the heat transfer enhancement due to piezoelectric fan agitation is inversely proportional to the net mean flow rate produced by the rotary fan. Also, the pressure drop remains unaltered when the piezoelectric fan is turned ON. The numerical simulations are performed to understand the change in fluid dynamics after piezoelectric fan insertion. To determine the noise reduction characteristics of the porous geometry, a transmission loss is measured across it with the single mic method. The transmission loss of around 15dB is observed at 2000Hz, increasing further up to 20dB at frequencies greater than 3000Hz.