Mechanical, thermal, and heat transfer investigation of additively manufactured graphene nanoplatelet reinforced polymer composite lattice heat exchangers

Abstract

This study aims to evaluate the mechanical, thermal and heat transfer performance of graphene nanoplatelet (GNP) reinforced polymer composite lattice heat exchangers fabricated via additive manufacturing. The work investigates how varying GNP concentrations influence the structure–property–performance relationships of stereolithography-printed lattice components intended for thermal management applications. Diamond lattice heat exchanger geometries were produced using a polymer-based photosensitive resin containing 0.01, 0.05 and 0.1 Wt.% GNP. Mechanical performance was assessed through tensile and three-point bending tests. Microstructural analysis was conducted via scanning electron microscopy. Thermal characterization included thermogravimetric analysis and thermal conductivity measurements. Heat transfer performance was experimentally evaluated under three mass flow rates using energy balance and logarithmic mean temperature difference methods. Tensile and bending strengths peaked at 0.05 Wt.% GNP, reaching 37.81 MPa and 34.57 MPa, respectively, before declining at 0.1 Wt.% due to particle agglomeration. Thermal conductivity increased monotonically with GNP content, reaching 0.355 W/m·K at 0.1 Wt.% GNP, corresponding to a 36% enhancement over neat polymer. Heat transfer rates improved by up to 28.6% at the highest GNP loading and mass flow rate tested. This study provides an integrated evaluation linking material-scale characterization to functional heat exchanger performance for additively manufactured GNP reinforced polymer composites with lattice architecture, an approach that has not been previously reported in the literature.