Design of Complex Structured Monolithic Heat Sinks for Enhanced Air Cooling

The design and characterization of monolithic heat sinks, which can take the form of complex structures, is reported. The designs were conceived to augment heat transport for enhanced air cooling by exploiting clearly identified physical mechanisms, i.e., by streaming the flow through a two-dimensional array of polygonal ducts, by introducing flow-obstacleinduced local mixing, and by exploiting hydrodynamic instabilities to sustain flow unsteadiness. Fabrication of these unconventional designs was achieved by 3D printing plastic patterns and converting them into monolithic copper structures by investment casting. A direct simulation approach aided by analytical solutions and experimental validation was undertaken to quantify fluid flow and heat transfer parameters. The paper concludes by quantifying the performance enhancement of the proposed heat sink geometries relative to a conventional longitudinally finned heat sink. The merits of the proposed model monolithic heat sinks are also discussed.