Flow and heat transfer characteristics of adaptive latticework structure: The effect of wall boundaries

• Adaptive heat exchanger switches between latticework and straight channel. • Increasing the channel count reduces wall-fluid coupling effect. • The maximum heat exchange regulation coefficient reaches 4.297. • The maximum performance evaluation criteria reaches 1.499. • The internal flow fields of heat exchanger was visualized via PIV experiments. Industrial heat exchangers, crucial in energy systems, often encounter significant pressure drops due to traditional fixed-operating-condition designs. To overcome this technical challenge, we have innovatively developed an adaptive latticework heat exchanger (ALHE) utilizing shape memory alloys (SMA) that replicate latticework channel structures. Our goal is to address the current limitations in thermo-hydraulic regulation. To achieve this, we conducted optimization studies through a combination of numerical simulations and particle image velocimetry experiments. The research indicated that the wall boundary conditions of conventional latticework structures represent a critical breakthrough point. By varying the number of interconnected channels, we can more effectively investigate the influence of wall boundaries on the thermo-hydraulic performance of the ALHE. It has been observed that when the SMA warpage value (Δ X ) equals the hydraulic diameter ( D h ), the number of ALHE channels significantly influences their thermo-hydraulic performance. When Δ X < D h , the thermo-hydraulic performance becomes independent of the number of channels. Flow field analysis revealed that the near-wall fluid in Channel One of the ALHE (1 channel) exhibited transverse ( X direction) and longitudinal ( Z direction) velocity enhancements of 103.23 % and 275.75 %, respectively, compared to Channel Four of the ALHE at Δ X = D h . Mechanistic analysis suggests that at Δ X = D h , as the number of channels increases, the wall’s influence on fluid flow diminishes due to a reduction in both the proportion and intensity of the fluid impact zone, thereby weakening the impact cooling effect. Numerical results demonstrate that the 1 channel exhibits the highest heat transfer and resistance regulation performance, with values of 4.297 and 37.948, respectively, while Channel Two of the ALHE achieves the best performance factor, with a maximum of 1.499. This research provides a robust foundation for the optimization and application of ALHE systems.