Thermal Stress Accommodation in Sodium/Inconel 718 Heat Pipes

Abstract In this study, sodium/Inconel 718 heat pipes with and without topological capillary were designed and fabricated in China Academy of Aerospace Aerodynamics. Then their startup properties were investigated systematically. It was found that startup temperature of sodium/Inconel 718 heat pipes was 420oC. During startup tests, all the heat pipes startup successfully. Topological capillary did not affect startup properties of sodium/Inconel 718 heat pipes. After tests, all the heat pipes still kept their integrity. Thermal deformation was not observed. A further thermal stress simulation indicated that topological capillary could accommodate thermal stresses in sodium/Inconel 718 heat pipes. With topological capillary addition, thermal stresses in the heat pipes decreased by about 21%. Moreover, the bended sodium/Inconel 718 heat pipe could startup successfully in an anti-gravity condition, being instructive for development of flexible and anti-gravity high temperature heat pipes.