Kinetic heat sink

Abstract

Conventional heat sinks for processors achieve improved heat transfer efficiency by impinging ambient air over stationary fins. Further improvement in the air film heat transfer coefficient through increased air speed becomes asymptotic and invariably results in undesirable acoustic noise. The Kinetic Heat Sink (KHS) is a novel concept that utilizes rotating metals fins to transfer heat to the ambient air. The configuration allows high-speed relative motion between surrounding air and fins with the potential of a high heat transfer coefficient at practical flow rates and rotational speeds. Improved efficiency of heat transfer is anticipated because of higher relative tangential velocities offered by the rotating fins and moving air compared to a conventional heat sink configuration. The need to move the fins relative to the stationary heat source, however, imposes a technical challenge. A highly conductive thin liquid film to couple the stationary heat source to the moving fins is required to demonstrate the merit of the KHS. The concept of the KHS has been evaluated in a number of prototypes that have been built and tested. The lessons learnt through a series of prototype KHS designs are summarized. The technical and performance challenges encountered during the feasibility testing of a KHS are then outlined. Copyright© (2010) by IMAPS - International Microelectronics & Packaging Society.