Design for Additive Manufacturing of high performance heat exchangers

Abstract

Heat exchangers are integral parts for thermal management and find countless applications in automotive, aerospace, energy, nuclear power plants, HVAC, etc. Due to intensive research & development and technological advancements in manufacturing technologies, there is an increasing rise in demand for high-performance heat exchangers. In the automotive and aerospace industries, heat exchangers are expected to deliver better thermal efficiency and improve the system’s overall functionality in which they are installed by saving space and being lightweight. Additive Manufacturing (AM) is a ground-breaking and promising technology that offers avenues of opportunities to manufacture parts that were almost impossible to be produced with conventional manufacturing and can improve part performance with lightweight and compact designs. Laser-Based Powder Bed Fusion (LPBF), one of the well-known AM techniques, provides freedom to design complex geometries and fabricate them in a layer-by-layer fashion by exposing a high-density laser on a vertically moving powder bed. The study focuses on the application of AM in re-designing heat exchangers under given design requirements using LPBF. It includes exploring Triply Periodic Minimal Surfaces (TPMS) based structures such as gyroid and realizing them as heat exchanger core. Computational gyroid-based heat exchanger core models were designed and analyzed for thermal and fluid dynamics characteristics. A parametric study and analysis based on gyroid TPMS network type, periodic length, thickness, aspect ratio, and functional grading were carried out to optimize heat exchanger performance as per design conditions and validate their manufacturability using LPBF. Successful printable designs were further used to develop and manufacture prototypes. The study concludes with a comparison between additively manufactured gyroid-based design and conventional shell-and-tube design based on the thermal performance from CFD analysis and the weight of prototypes. It was found that the thermal performance from CFD analysis showed an 18.96% improvement, whereas weight was reduced by 14.8% for the gyroid-based design as compared to the conventional shell-and-tube design.