A Novel Laser-Processed Condensing Heat Exchanger for Space Systems

Condensing heat exchangers (CHXs) are commonly used for spacecraft life support as part of the overall environmental control subsystem. They allow water from humid air to be collected and circulated back into the water reclamation unit on orbit. To optimize such a system, limited allowable pressure drops and a specified vapor recuperation rate must be achievable. Traditionally, numerical models rely on established heat transfer and pressure drop correlations. This project investigated the addition of dimples to the heat exchanger surface for improved convective heat transfer, but this meant that the flat-plate correlations initially used in the laminar model needed to be updated to a k-ω turbulence model. Additionally, manufacturing advantages of electroplating the components together were investigated and documented through microscopy analyses. The wetting properties of the system were achieved through a laser-processing treatment via dual-pulse femtosecond laser surface processing, which also provides microbial tolerance to the hardware. The aftereffects of laser processing on the electroplated system were also investigated. This project’s effort toward reducing overall manufacturing time and yielding enhanced performance over current state-of-the-art space CHX systems has applications for long-duration spaceflight, such as a future Mars mission.