Numerical and Experimental Studies of Ultra Low Profile Three-dimensional Air-cooled Heat Sinks Made Using a Novel Manufacturing Method

The continued increase in electronic device packaging densities is placing ever more challenging performance requirements on air-cooled heat sinks. In cases where the state-of-the-art heat sink technology is unable of to meet these requirements, this often results in either a relaxation of design specifications, or the exploration of other thermal management technologies better able to handle high heat density applications, such as liquid cooling. Both of these approaches provide challenges to equipment designers, as relaxing requirements does not allow for a scale-able path to increased device densities and their associated functionality, while incorporating new thermal management technologies often requires major hardware redesigns, which has significant cost implications. In this work we explore the use of air-cooled heat sinks incorporating three-dimensional features, so-called three-dimensional heat sinks (3DHS), that enhance heat transfer through a number of different physical mechanisms, as an approach to further extending the limits of air cooling. An ultra low profile heat sink application is targeted due to the significant thermal challenges associated with restrictions on heat sink height. We also present details on a novel manufacturing method that has significant cost advantages over other fabrication methods such as investment casting and direct metal printing. Experimental characterization of 3DHS performance is conducted in a wind tunnel test apparatus as a function of heat sink design parameters, inlet air mass flow rate and flow bypass above the heat sink.