This work studies the thermal and hydrodynamic performances of pyramidal fin arrays produced using the cold spray process as an additive manufacturing process. Near-net shaped pyramidal fin arrays of various materials were manufactured (pure aluminum, pure nickel and stainless steel 304). Fin array characterization such as fin porosity level and surface roughness evaluation was performed. The nickel pyramidal fin array is shown to be rougher compared to the two other materials used in this study. The results obtained show a lower thermal efficiency for stainless steel 304 whereas the performances of the aluminum and nickel fin arrays are similar. The multi-material sample has a better thermal efficiency than stainless steel 304, which constitutes the proof of concept of using a streamwise anisotropic fin array.

This work studies the manufacturability of pyramidal fin arrays produced using cold gas dynamic spraying. Near-net shape pyramidal fins of various sizes were formed and tested. The fin arrays were characterized and their heat transfer properties were assessed. Results obtained correlate well with data published for banks of tubes at a similar dimensionless pitch, and show that fins produced by cold spraying outperform traditional straight-cut fins at the same fin density.

Heat exchangers play a vital role in ongoing efforts to conserve energy. Plate-type heat exchangers typically consist of two flat separated flow paths in which heat transfer enhancing matrices are inserted. The combined effects of small irregular hydraulic diameters along with elevated heat transfer areas results in highly-efficient heat transfer to the external fluid. This allows for very versatile and compact heat exchanger designs. Typical plate-type heat exchanger fabrication methods such as brazing are labour intensive and limit post-processing operations like welding. In this paper, a novel micro-heat exchanger fabrication method using recently patented technologies is presented. The approach uses thermal spray processes such as Pulsed Gas Dynamic Spraying (PGDS) as an alternative to brazing for the production of a pressure barrier and integration of flow headers. Mesh wafer surfaces sealed using PGDS