Co-design of a LPBF-manufactured Supercritical Carbon Dioxide Heat Exchanger

Laser powder bed fusion (LPBF) provides significant design flexibility in terms of the geometries that can be produced. Through careful control of the printing parameters, it is possible to print structures such as thin internal channels or complex lattices that would be difficult or even impossible to produce via conventional machining methods. However, there are still limitations to the process that can impact the fabricability of a part. Thus, when designing parts for LBPF, it is crucial for the part geometry and processing conditions to inform each other so that an effective part can be fabricated successfully. In this work, this idea of co-design was employed to produce a supercritical CO₂ recuperator. This heat exchanger was intended to operate under high temperatures and pressures, so the nickel-based superalloy Haynes 282 was selected for printing. A series of experimental builds were performed to determine optimal processing parameters and part design. Post-processing methods were also considered, such as heat treatments and internal smoothing methods. Ultimately, this led to the formulation of a final design and processing workflow that allowed for the successful fabrication of a functional heat exchanger with a compact form factor but high thermal rating.