Design of Periodic Cellular Structures for Heat Exchanger Applications

Powder based metal additive manufacturing processes generally produce parts with a textured surface. Although surface roughness is undesirable in most cases, it can be advantageous for applications such as heat exchangers or catalyst support structures. While stochastic metal foams have been used for these applications, it is not possible to tailor the foam geometry to the application. SFF techniques permit designers to use different cell geometries and orientations to achieve specific performance objectives. More specifically, the unit cell type and size, ligament size, and cell orientation have a considerable influence on surface area, volume, density and fluid flow behavior of the lattice structure. This paper illustrates the effect of the orientation of hexagonal periodic cellular structures on heat transfer and pressure drop. Finite element analysis of air flowing through the hot hexagonal periodic cellular structures shows the effect of orientation on heat transfer and pressure drop. The analysis indicates that the ideal orientation is dependent on the specific application.