Numerical evaluation of additively manufactured lattice architectures for heat sink applications

Abstract

Tailoring the architectural characteristics of lattice materials at different length scales, from nano to macro, has become tenable with emerging advances in additive manufacturing. Cumulative needs of high heat dissipation rates and structural requirements along with lightweight constraints have led to the development of several heat sink fins with lattice architectures in heat exchange-applications. Here, we numerically investigate the potential of polymer-based 3D printed lattice architectures as extended heat transfer surfaces and examine the forced-convection characteristics of simple-cubic, body-centered-cubic and face-centered-cubic trusses as well as simple-cubic plate, and Kelvin and Octet periodic lattices with mesostructured architecture. All these lattices have a porosity of 77% (relative density ~23%) and surface area density in the range of 1500−2400m2/m3. Thermal and hydraulic finite element studies were conducted for fluid flow over the lattice architectures for low Reynolds number in the range of 50−360 and constant wall temperature conditions. The performance of different cell-topologies is characterized in terms of exit fluid temperature, heat transfer coefficient with respect to different reference surface areas, pressure drop per unit length, Colburn factor j, Fanning friction factor f and area goodness factor j/f. The study of the influence of thermal conductivity on heat transfer rate reveals that the polymer-based architected heat sinks perform close to their metallic counterparts when evaluated on per unit mass basis. Furthermore, body-centered-cubic truss, simple-cubic plate, and Kelvin and Octet lattice-cells were found to exhibit better thermal performance than some microchannel and open-cell foam heat sinks.