Abstract
We present an experimental study on buoyancy-driven convection transport in additively manufactured lattices comprising of cubic unit cells, where we have studied the effect of lattice aspect ratio (width-to-height ratio) and heating orientation with respect to the gravity vector. The lattices were manufactured via Binder jetting process in Stainless Steel 420 (with 40% bronze infiltration). The solid-phase thermal conductivity was measured on a solid sample manufactured through the same technique and was found to be 20.8 W/mK. Each lattice configuration had a porosity of 0.87. These lattices with aspect ratio varying from 0.5 to 2 and three different heating orientations, viz. bottom wall (0°), side wall (90°), and top wall (180°) heating, were tested for Rayleigh numbers ranging from 105 to 4 × 105. We found that the lowest aspect ratio lattice had the highest convective heat transfer coefficient for all three heating orientations. Further, an inter-comparison of the heating orientations at a fixed lattice aspect ratio revealed that the sideways heating orientation (90°) had the highest heat transfer, followed by bottom wall (0°) and top wall heating orientations (180°).
