Design of an Additively Manufactured Vapor Chamber Heat Exchanger for Space Applications

In space exploration, the thermal management system is an essential and critical system that helps ensure that the electronic components within the spacecraft function correctly under extreme environment conditions. Phase Change Material (PCM) heat sinks are ideal for a wide variety of applications because the latent heat associated with melting and freezing can store much more heat than sensible thermal storage alone. Both manned and unmanned spacecraft can benefit from PCM heat exchangers (HX). Since there is no atmosphere in outer space, heat can only be rejected using radiators, which radiate the heat to space. The heat sink conditions, and the power to be rejected, vary constantly as the spacecraft orbits the earth or moon. Without thermal storage, the radiator must be large enough to reject the highest power at the hottest heat sink. With PCM, the radiator can be sized for the average, rather than the maximum power. For spacecraft thermal management applications, it is essential to reduce the overall mass of on-board thermal storage system and minimize the temperature fluctuation when the environmental temperature changes dramatically. One method to maximize the mass ratio is to replace the solid heat transfer medium with the two-phase working fluid, which also reduces the thermal resistance can be reduced significantly. Prior work on this novel vapor chamber design has shown promising performance, and to overcome the complexity of conventional fabrication method, here this design is re-assessed and optimized for fabrication using additive manufacturing method. The additive manufacturing system used here is EOS M280 Direct Metal Laser Sintering system. Through this approach, it has eliminated the need of spacer and significantly reduced the assembly time and tedious vacuum process needed. The performance of this system is tested and compared with simulation results to validate this current design. The results have shown the advantages of using this new manufacturing technique and the possibility of further improve current design to allow better thermal performance. This paper also discusses the current limitation of this design and future work needed for this study.