Experimental and numerical analysis of the thermal performance of PCM-impregnated reticular structures obtained by additive manufacturing

This paper proposes a combined experimental and numerical analysis of the melting of three different paraffin waxes embedded in reticular structures fabricated by additive manufacturing. The parent material of the reticular structures is AlSi10Mg. Metal structures, having a 100 mm square base and a thickness of 20 mm, were printed between two 10 mm thick plates. Samples were positioned in an upright position and laterally heated applying different heat fluxes. Three different paraffins were tested, with different characteristic melting temperatures (42 °C, 55 °C, and 64 °C), which are suitable for electronics cooling applications. Four different structures were tested, having a cell length of 5 mm and 10 mm, and porosities of 0.87 and 0.93. Besides the experimental tests, numerical simulations of the melting phenomenon were carried out using a purely conductive model implemented in ANSYS Fluent. The discretized numerical domains represented just small repetitive portions of the test modules, thus allowing substantial computational time savings. This simplified method has been proven to yield results that are in good agreement with the experimental data. The main outcome of this work is the setup of the simplified numerical procedure, which was then validated and used to investigate the effectiveness of the considered structures in diffusing heat into the low thermal conductivity phase change materials. It was concluded that the best overall thermal performance can be obtained with low porosity and low cell size since this enables faster melting processes and better surface temperature control.