Heat transfer enhancement using flow-induced vibration of a microfin array

Abstract

Advanced computers are facing thermal engineering challenges from both high heat generation due to rapid performance improvement and the reduction of an available heat removal surface due to large packaging density. Efficient cooling technology is desired to provide reliable operation of microelectronic devices. This paper investigates the feasibility of heat transfer enhancement in laminar how using the flow-induced vibration of a microfin array. The microfins are initially bent due to the residual stress difference. In order to characterize the dynamics of the microfin flow-induced vibration, a microfin sensor is fabricated. Increase in air velocity provides larger vibrating deflection, while the vibrating frequency of the microfin is independent of the air velocity. The thermal resistances are measured to evaluate the thermal performance of thr: microfin heat sink and compared with those of a plain-wall heat sink. For a fluid velocity of 4.4 m/s, the thermal resistance of the microfin array heat sink is measured to be 4.45 degreesC/W and that of the plain-wall heat sink to be 4.69 degreesC/W, which indicates a 5.5% cooling enhancement. A; a flow velocity of 5.5 m/s, the thermal resistance of the microfin array heat sink is decreased by 11.5%. From the experimental investigations, it is concluded that the vibrating deflection plays a key role in enhancing the heat transfer rate. (C) 2001 Elsevier Science B.V. All rights reserved.