A parametric study of heat transfer in an air-cooled heat sink enhanced by actuated plates

Abstract

Heat transfer in air-cooled heat sinks must be improved to meet thermal management requirements of modern microelectronics devices. This need is addressed by putting agitator plates into channels of a heat sink so that heat transfer is enhanced by agitation. A proof-of-concept exercise was computationally conducted in a single channel consisting of uniform-temperature base and two side walls and an adiabatic fourth wall. The channel side walls are fins of the heat sink fin array. The agitator plate is within the channel. Air flows through the channel and the agitator plate generates periodic motion in a transverse direction to the air flow and to the channel surface. Turbulence is generated along the tip of the agitator plate due to its periodical motion, resulting in substantial heat transfer enhancement in the channel. Heat transfer is enhanced by 61% by agitation for a representative situation. Translational operation of the plate induces 33% more heat transfer than a corresponding flapping operation. Heat transfer on the base surface increases sharply as the tip gap size between it and the agitator plate tip is decreased, while heat transfer on the sidewalls is insensitive to the tip gap size. Heat transfer from the channel wall to the flow increases linearly with increases of amplitude or frequency of the agitator plate. The primary operational parameter to the problem is the product of amplitude and frequency, with amplitude being slightly more influential than frequency.