Heat transfer enhancement of a heat sink using electromagnetically-driven oscillating sheet array

Abstract

In this study, an oscillating sheet array device driven by electromagnetic force has been proposed. This device can be integrated with a heat sink to enhance heat transfer coefficient. Typically, the fin gaps of a heat sink for natural convection need to be sparse. If the fin gaps are large enough, the boundary layers that develop along the surface of the fins will not overlap and result in optimal performance. Since the fin gaps are sparse, it is allowed to insert an oscillating sheet between the gaps. They can produce airflow and break boundary layers to enhance heat transfer coefficient. The dimension of the heat sink under study with nine fins is 80 mm (L) * 80 mm (W) * 50 mm (H) and the fin gaps are 8 mm. The main advantages of the oscillating sheet array are no bearing structure and small volume change - it only increases the total heat sink volume by 0.6%. Moreover, its simplicity makes it a highly reliable and low cost device. The driving current can be either DC PWM or AC between 3 V - 12 V so it is compatible with most electronic devices. According to the cooling experiment, vertically arranged array can decrease the thermal resistance of the tested heat sink from 3.41 to 1.61 while consuming 0.66 W.