Conformal geometric design and additive manufacturing for special-shaped TPMS heat exchangers

Abstract

Additive manufacturing (AM) technology has advanced the development of heat exchangers based on Triply periodic minimal surfaces (TPMS). Although TPMS-based heat exchangers enhanced heat transfer capabilities, designing engineering special-shaped heat exchangers that conform to AM process constraints required reducing supports and preventing leakage. This paper proposed a novel conformal filling method to design special-shaped TPMS heat exchangers, which improved fragmentation and leakage by locally altering the cell shape. The study investigated ten different structures based on tubes, Gyroid, Schwarz-D, I-WP, and Primitive and each filled in various orientations. The effects of design parameters of TPMS heat exchangers were investigated through numerical and experimental studies. How controlling the shape and manufacturing parameters during the fabrication process was investigated to ensure the designed structure would not leak. Different TPMS metal heat exchangers, fabricated by AlSi10Mg powder using Laser powder bed fusion (L-PBF), were evaluated by micro-computed tomography (μ-CT) to verify the completeness of the heat exchanger channels. Results showed that the method improved the heat transfer efficiency by enhancing the flow uniformity. Conformal I-WP structure achieved a twice increase and Primitive structure enhanced by three times. This method benefits the manufacturing and heat exchange capabilities of AM heat exchangers.