Gyroid-structured heat exchanger optimization via lattice geometric manipulation for enhanced thermo-hydraulic performance: an experimental and numerical research

The escalating challenges in thermal management have rendered conventional heat exchange configurations increasingly inadequate for meeting the stringent demands of onboard heat exchangers in aircraft engines. Triply periodic minimal surface (TPMS) structures, particularly the Gyroid configuration, have received significant attention due to their superior thermal efficiency and mechanical robustness. However, prohibitively high flow resistance remains a critical barrier to the industrial adoption of TPMS-structured heat exchangers, and research on optimizing their hydraulic performance remains sparse. To address this limitation, this study introduces a lattice geometric manipulation strategy based on the implicit governing equation. This approach induces a streamwise-stretched morphology in the Gyroid structure, thereby altering related performance. A combined experimental and numerical method was employed to systematically evaluate the influence of lattice manipulation on thermo-hydraulic-mechanical performance, flow characteristics, and comprehensive performance. Key findings reveal that the manipulated Gyroid structures achieve substantial flow resistance reduction with only marginal compromises in thermal performance. For instance, the manipulated structure exhibits an 80 % reduction in pressure drop at the expense of a 28 % decrease in heat transfer rate relative to the original structure. This trade-off arises from attenuated wall-induced fluid disturbance and reduced flow channel tortuosity following lattice stretching. Manipulated flow fields are characterized by diminished overall velocity, weakened intensity of helical motion, and enhanced flow uniformity. Although geometric lattice manipulation reduces the mechanical strength of Gyroid structures, the magnitude of weakening remains within acceptable limits. Empirical correlations (Nu ∼ Re, f ∼ Re) for original and manipulated structures, incorporating a dimensionless geometric parameter, were derived from experimental datasets. The manipulated Gyroid structures demonstrate a 10 % improvement in overall performance compared to the original structure. The advancements achieved by this work include proposing a flow resistance-focused optimization method for TPMS-structured heat exchangers, establishing a quantitative guideline for flow uniformity-driven hydraulic optimization, and presenting the first dimensionless geometric parameter-integrated empirical correlations.