Enhanced gaseous natural convection from micro-scale fin structures using acoustic stimulation

Abstract

This paper investigates the effect of acoustic stimulation on natural convection heat transfer in micro-scale fin structures. Enhancement of heat transfer from electronic components enclosed within compact geometries is a key goal in thermal management. Among the techniques to enhance heat transfer, extended surface is a simple approach to achieve the goal. However, micro scale fin heat sinks have little effect on natural convection heat transfer. Previous work has shown that heat transfer via flow-induced vibration in a micro fin array can be enhanced, but only in a forced convection scheme with high flow rates. Acoustic stimulation has also been investigated in boiling and we extend this method of stimulation to enhance gaseous natural convection. The acoustic stimulation is generated using a speaker placed close to the micro fin array device. Waves of varying amplitude and frequency are generated and device surface temperatures recorded along with the speaker velocities, measured using Laser Doppler Velocimetry. The results obtained suggest that natural convection heat transfer can be enhanced using acoustic stimulation in micro-scale fin structures where the fins contribute negligible effect on overall heat transfer, and the enhancement varies with fin geometries. The results indicate that gaseous natural convection is feasible as a thermal management scheme in micro fin structures for low heat flux applications. Future works will be devoted to finding the resonance frequency of natural convection in micro-scale fin structures that can enhance heat transfer dramatically with little additional power consumption.