CHAPTER 8 PROGRESS IN HIGH-PERFORMANCE HEAT-TRANSFER TECHNOLOGY ENABLED BY ADDITIVE MANUFACTURING

Advancements in metal additive manufacturing (AM) are yielding design concepts in diverse fields that reduce discrete part counts, consolidate processing steps, and raise technical performance. AM is enabling novel high-performance convective heat-transfer geometries with applications in turbomachinery, electronics thermal management, building energy systems, power generation cycles, and actively cooled manufacturing tooling. This review traces progress of metal AM heat transfer technology over the past decade. At the feature-scale, findings are summarized for heat-transfer enhancement geometries enabled by AM including complex internal passages, surface modifications, pin fins, and lattice structures. Emphasis is placed on practical manufacturing considerations, such as the impacts of wall thickness and orientation. Performance trends for the AM-enabled geometries are compiled and compared with metrics that capture competing augmentations for heat-transfer enhancement and frictional loss, providing a mapping for different design applications. At the device-scale, this review presents progress toward practical-scale (∼ 1–100 kW) fluid-to-fluid heat exchangers (HXs) and potential commercialization. Different design approaches are surveyed, including reproduction of conventional HX geometries, application of AM-enabled lattice structures, and topology/shape optimization. While AM convective heat-transfer technology offers technical benefits and enables rapid customization, there are significant barriers to broader adoption. Key challenges are reviewed including support-structure requirements, minimum feature size limitations, difficulty in removing unsintered powder, limitation to single material construction, maximum build-volume limits, and the lack of standards for AM design software interoperability. Additionally, there are open questions including whether AM can become repeatable or “turnkey,” whether the complex mechanics of metal AM can be captured at the design stage, and the ultimate economics of AM for heat-transfer applications. The extent to which these challenges can be addressed and outcomes for these questions will determine the prospects for AM heat-transfer technology and translation from specialty applications to mainstream commercialization.