Experimental Characterization of a Microchannel Heat Sink Made by Additive Manufacturing

Abstract

Microchannel heat sinks allow removal of dense heat loads from high-power electronic devices at modest chip temperature rises. Such heat sinks are produced primarily using conventional subtractive machining techniques or anisotropic chemical etching, which restricts the geometric features that can be produced. Owing to their layer-by-layer and direct-write approaches, additive manufacturing (AM) technologies enable more design-driven fabrication and offer improved geometric freedom and complexity. There has been limited assessment of the capability of AM process to produce microchannel heat sinks that meet nominal geometry and performance targets, even for conventional designs. Direct metal laser sintering (DMLS) was used to demonstrate additive manufacture of an aluminum alloy (AlSi10Mg) microchannel heat sink with straight, parallel channels (D H = 500 μm). The thermal and hydraulic performance of the heat sink was characterized over a range of mass fluxes from 500 kg/m2s to 2000 kg/m2s using water as the working fluid. The straight microchannel design allows these experimental results to be directly compared against established predictions from the literature. The comparison facilitates an assessment of the role of geometric or property differences introduced by the AM process (relative to conventional fabrication approaches) in realizing the nominal design. The insights gained from this evaluation, which offers an improved description of the fabrication constraints and sets expectations on fidelity to the design targets, will be used in ongoing work that explores heat sink designs exploiting the full range of geometric complexity made possible with additive manufacturing.