Loop Heat Pipe Manufacturing via DMLS for CubeSAT Applications

Advanced Cooling Technologies, Inc. (ACT) proposes to develop a low-cost Loop Heat Pipe (LHP) evaporator using a technique known as Direct Metal Laser Sintering (DMLS), otherwise known as 3D printing, to produce low-cost LHPs to be used in CubeSat and SmallSat applications. The wick structure in an LHP assumes the role of a pump in a standard loop, pumping liquid from the lower pressure condenser to the higher pressure evaporator by capillary forces. The overall thermal performance of the system is therefore highly dependent on the in-situ characteristics of the wick structure. Current LHP wick manufacturing and installation processes are cumbersome, labor intensive, and suffer from a low yield rate. Specifically, the primary wick?s hydrodynamic characteristics and sealing integrity to the envelope are critical to heat transport, start-up, shut down and overall reliability. It is estimated that the cost to produce an LHP evaporator, including the attachment of the bayonet, secondary wick and compensation chamber, accounts for approximately 75% of the total system?s manufacturing cost. By 3D printing an evaporator envelope with an integral porous primary wick structure, the overall complexity and cost of the design can be significantly reduced.