A Dual-Medium Model-Based Method for Rapid Thermal Performance Analysis of TPMS Porous Heat Exchange Structures

The triply periodic minimal surface (TPMS) structure demonstrates significant potential in the field of active heat transfer. This is due to its high specific surface area and controllable pore connectivity. However, its intricate geometric features result in notable computational costs during RANS-based CFD simulation, greatly limiting the efficiency of its design and optimization processes. Although existing equivalent approaches (e.g., the volume averaging method and the porous media model) have reduced the computational burden to some extent, they still suffer from limitations. Theseinclude insufficient sensitivity to microstructural features and low accuracy in characterizing convective heat transfer. In order to address the temperature-field prediction biases caused by the above limitations when filling TPMS on a large scale, this paper proposes a rapid analytical method based on a dual-medium model. The core idea of this method is to idealize the TPMS structure as a continuous solid thermal conductive medium and to homogenize its internal flow channels into a coexistent Darcy-Forchheimer fluid medium. The thermal conductivity tensor of the equivalent solid is accurately calculated via the homogenization method, whereas convective heat transfer in the fluid medium is characterized using empirical correlation equations. Ultimately, a rapid analytical model coupling solid heat conduction and fluid convection is developed at the macroscopic scale. Numerical examples show that, compared with traditional computational fluid dynamics (CFD) methods, this method improves computational efficiency by approximately 22 times while retaining high accuracy, thus providing an effective tool for the rapid design and performance assessment of TPMS-based active heat transfer structures.