Effects of tip gap and amplitude of piezoelectric fans on the performance of heat sinks in microelectronic cooling

Abstract

Piezoelectric fan is a promising option for cooling microelectronic devices owing to its unique features such as no electromagnetic noise, low power consumption and minimum space requirement. The recent interest is to integrate the piezoelectric fans (piezofans) with heat sink; this idea is widely accepted and researches are still underway. This article presents experimental analysis on the effects of tip gap (d) and amplitude of piezofan vibration (a) on the heat transfer characteristics of finned heat sinks. Two heat sink configurations, namely A and B (with two and four fins respectively) each of which is arranged with three piezofans, are considered for the study. The transient temperature distributions for cases with and without piezofans are obtained for both the configurations, and compared. The heat transfer coefficient, thermal impedance, Nusselt number and Reynolds number are investigated as functions of d and a. The effect of a on the fan effectiveness is also analyzed. It is observed that the configuration B has better cooling performance compared to A. Among the tested ranges of d and a, the case with least tip gap (d = 0.03) and highest amplitude (a = 5.29) is found to be the best; at this setting, the fan effectiveness is increased to almost 4 times compared to the case without piezofans.

Thermal performance of a dual-sided multiple fans system with a piezoelectric actuator on LEDs

“…To combine the effect of the Mylar plate width and the vibrating amplitude, the characteristic length (L PZT ) is defined as the hydraulic diameter, as described in Eq. (8).…”

“…Abdullah et al [8] investigated the thermal characteristics of the heat sink with three piezofans, and the results showed that the fan's effectiveness was increased to almost 4 times than the case without piezofans. Sufian et al [9] investigated the thermal performance of two piezoelectric fans in multi-LED packages.…”

The Influence of Surface Roughness on the Flow Fields Generated by an Oscillating Cantilever

“…This is in contrast to much of the literature on oscillating piezoelectric fans where airflow emanates in a forward direction from the fan tip. The cooling capabilities of these airflows as they impinge on a heated surface have been studied extensively ( [5], [11], [12], [13]). The lateral wake regions in the current work Fig.…”

Direct actuation of small-scale motions for enhanced heat transfer in heated channels

“…The most recent studies focus on the thermal performance of plate-fin heat sinks and the optimization of the position of the piezo fan based on the peak-to-peak displacement amplitude, proximity to the heat source, orientation of the fan and/or number of fins of the heat sink needed to obtain the maximum performance out of the piezoelectric fan arrays. Such investigations can be observed in the work from Abdullah et al [13] and Li et al [14] Most of these investigations have been done using piezoelectric fans with a resonance frequency not larger than 120Hz with a fan length between 4 and 8cm and a footprint area on the order of 6-9cm 2 and a peak-to-peak displacement amplitudes of approximately 10-20mm and without any additional air flow source.…”