Directed Energy Deposition: an Additive Manufacturing Technology for Large High-Temperature Compact Heat Exchangers, Process Characterization and Fluid Dynamic Performance

Heat exchangers are essential for temperature regulation across various industries, from everyday applications to space exploration. Over time, these devices have evolved from simple clay vessels to complex structures made from advanced metal alloys and ceramics. In modern engineering, additive manufacturing (AM) has revolutionized heat exchanger production, enabling the creation of thin-walled structures with complex internal channels designed for efficient fluid flow. This is particularly critical in industries such as aerospace, power generation, and manufacturing, where components must be compact, lightweight, and capable of withstanding extreme temperatures and pressures. However, traditional AM methods like laser powder bed fusion (L-PBF) are constrained by size limitations, necessitating new manufacturing techniques to meet industry demands for compact large scale heat exchangers.

This research addresses the challenges of developing the Laser Powder Directed Energy Deposition (LP-DED) process for extreme-environment heat exchangers. Process and flow test experiments were conducted, along with comprehensive characterization of LP-DED-fabricated microchannels, which are thin-walled (1 mm) and capable of containing cryogenic or high-temperature pressurized fluids. The results from the research establishes LP-DED as a viable technology for heat exchanger fabrication by addressing challenges related to geometry, wall thickness, surface texture, and the fluid dynamics of these unique AM surfaces.