Optimization of Air-Cooled Heat Exchangers with Diamond Triply Periodic Minimal Surface Structures through Computational Fluid Dynamics and Design of Experiments

Recent advancements in triply periodic minimal surfaces (TPMS) have led to their promising use in efficient heat removal for compact systems. TPMS-based heat exchangers offer high surface area, adjustable porosity, and optimized fluid flow, yet there is a gap in research on optimizing their design for improved thermal performance and pressure management, especially in air-cooled heat exchangers. This study examines the thermal and fluid dynamic performance of an air-cooled heat exchanger using a sheet Diamond TPMS structure. A conjugate heat transfer analysis was performed using ANSYS Fluent to evaluate various configurations. A simplified model was created in nTop within a 30 mm x 30 mm x 30 mm design space. The Design of Experiments (DoE) methodology was employed to systematically explore key design variables like TPMS unit cell size, wall thickness, and material selection (Aluminium vs. Copper). Results indicate that increasing unit cell sizes and decreasing wall thickness significantly enhance thermal performance and fluid flow while reducing pressure drop. Specifically, reducing wall thickness from 1.2 mm to 0.7 mm increased heat transfer rates and cold air flow rates by 37% and 36%, respectively, while lowering pressure drop by 68%. Additionally, increasing the unit cell size from 7.5 mm to 20 mm improved heat transfer rates by 25% and cold air flow rates by 206%. The choice of material had a minor impact on heat transfer outcomes, underscoring the importance of geometric configuration and porosity. This research establishes the feasibility of TPMS structures in heat exchanger designs and offers a systematic approach using DoE and CFD analysis to identify optimal configurations, enhancing cooling performance in various industrial applications.