Convective heat transfer in a lightweight multifunctional sandwich panel with X-type metallic lattice core

Abstract

The thermo-fluidic characteristics of an ultralightweight X-type lattice cored sandwich panel with simultaneous thermal and mechanical load bearing capabilities are studied both experimentally and numerically. Comparisons with competing sandwich panels with periodic cellular material (PCM) cores are carried out at a similar porosity level. For a given Reynolds number, the highly porous X-lattice cored sandwich panel provides up to 38% higher overall Nusselt number than tetrahedral lattice cored sandwich panel, while exhibits comparable heat transfer performance to Kagome lattice cored sandwich panel. Although brazed joints between the lattice core and the facesheets induce both transverse and longitudinal vortices, limited flow mixing asa result of smooth mainstream in the X-lattice leads to inferior average Nusslet number on both the facesheets and ligaments relative to tetrahedral lattice cored sandwich panel. However, the X-lattice has a 66% higher surface area density than tetrahedral lattice, which acts as the main heat transfer enhancement mechanism. Relative to the reference ones, the X-lattice cored sandwich not only provides an overall Nusselt number up to 77% higher for a given pumping power, but also exhibits evidently lower pressure drop for a given Reynolds number. Therefore, such metallic lattices fabricated using the simple metal sheet folding method are superior for lightweight thermal management systems where a cooling fluid with small specific heat is driven by limited pumping power in a long cooling channel.