Analysis of Thermo-Hydraulic Behavior of a Compact Heat Exchanger with TPMS Structures
Abstract
This paper presents the design and numerical evaluation of a compact heat exchanger employing TPMS (Triply Periodic Minimal Surfaces) structures. Attention is focused on the characteristics of selected TPMS structures, their implementation in the heat exchanger design, and the selection of a suitable geometric configuration in terms of thermal performance and pressure losses. The heat exchanger geometry was designed in Creo Parametric, while the TPMS structures themselves were generated using nTop software. Their thermo-hydraulic properties were evaluated by numerical simulations in ANSYS CFX, focusing on the influence of geometric and operating parameters. Based on the numerical simulation results, the most suitable variant was selected as a compromise between the achieved thermal performance and hydraulic losses.
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Introduction
Heat exchangers are an important component of many technological and energy systems, where they provide the transfer of thermal energy between two or more media. Their structural arrangement significantly affects heat-transfer intensity, pressure losses, dimensions, and the overall efficiency of the device. Therefore, when designing modern heat exchangers, it is important to identify geometric solutions that enable efficient use of the available space while maintaining favorable thermal and hydraulic characteristics.
One promising approach to the design of compact heat exchangers is the use of TPMS (Triply Periodic Minimal Surfaces) structures. This is a design concept in which the geometry repeats in three spatial directions and is characterized by zero mean curvature. Their specific geometry makes it possible to create complex, interconnected three-dimensional channels with a high ratio of heat-transfer area to the total volume of the device, thereby providing favorable conditions for heat-transfer intensification while minimizing the space required for installation of the device.
When TPMS structures are applied in heat exchangers, the available heat-transfer area increases substantially compared with conventional geometric solutions. The complex nature of the flow within the structure also promotes fluid mixing and disruption of the thermal boundary layer, which may increase the heat-transfer coefficient. Another advantage of TPMS structures is the possibility of parametric control of their geometry, for example through the unit-cell size, relative density, or wall thickness. By varying these parameters, both the thermal and hydraulic characteristics of the resulting structure can be modified. The use of TPMS structures in heat exchangers is also closely associated with the development of additive manufacturing technologies. These technologies enable the fabrication of geometrically complex structures that could be produced by conventional manufacturing processes only with substantial limitations.
Conclusion
The numerical simulation results showed that the characteristics of the proposed heat exchanger are strongly influenced not only by the TPMS structure type itself, but also by the choice of its geometric parameters and operating conditions. It was confirmed that increasing the flow velocity increases the heat-transfer coefficient and thermal power, while simultaneously causing a pronounced rise in pressure losses. Among the compared variants, the Gyroid structure with a wall thickness of 0.7 mm and a cell size of 10 mm was found to be the most advantageous. The numerical analysis clearly confirmed that the final geometry cannot be selected solely on the basis of maximizing heat transfer; instead, it must represent an optimization compromise between the intensity of heat transport between the media and the hydrodynamic losses of the device. The findings obtained in the presented research provide an appropriate methodological and design basis for follow-up studies. Further research should focus primarily on additive manufacturing of the proposed heat exchanger, its experimental verification, dimensional optimization for specific operating applications, and assessment of the long-term operational reliability of the proposed solution.
References
- Blanquer, S., et al. (2017). Surface curvature in triply-periodic minimal surface architectures as a distinct design parameter in preparing advanced tissue engineering scaffolds. Biofabrication, *9*, 025001.
- Feng, J., et al. (2022). Triply periodic minimal surface (TPMS) porous structures: From multi-scale design, precise additive manufacturing to multidisciplinary applications. International Journal of Extreme Manufacturing, *4*(2), 022001.
- Dutkowski, K., et al. (2022). Review of the state-of-the-art uses of minimal surfaces in heat transfer. Energies, *15*(21), 1-25.
- nTop, Inc. (2023). Thermal management guide: Heat exchanger design for additive manufacturing. nTop. https://ntopology.com
- Vlahinos, M., & O'Hara, R. (2020). Unlocking advanced heat exchanger design and simulation with nTop platform and ANSYS CFX [Technical report]. https://revolutioninsimulation.org
- E-konstruktér. (2015). Hustota a specifická hmotnost vody. https://e-konstrukter.cz/prakticka-informace/hustota-a-specificka-hmotnost-vody
- Kizek, J. (n.d.). Vybrané vlastnosti vody. https://jan.kizek.website.tuke.sk/tabulky/vlastnosti%20vody.htm
- Shah, R. K., & Sekulić, D. P. (2003). Fundamentals of heat exchanger design. John Wiley & Sons.