Flexible Heat Pipe for Space, Development and Test Validation

The proposed paper details the description of the development of the flexible link compatible with aluminum axially grooved heat pipes technology. The straight parts are classical extruded aluminum grooved profiles used for the most widely used heat pipes technologies in space applications, with high reliability and large space flight heritage. The flexible heat pipe is composed of a flexible junction to connect the straight extruded aluminum grooved standard profiles. The flexible joint contains a capillary structure, a flexible housing and welded connectors. The development process is detailed. Two Engineering Models with different technologies for the flexible capillary structures are manufactured and tested to validate their robustness and characterize their performances. These Engineering Models have been tested in the specific rotating test bench capable to simulate the micro-gravity fluid distribution to determine the optimal filling quantity in straight configuration. Then an extended performance characterization step is performed in several bent configurations from straight to stowed, with tilt up to 5mm with evaporator above the condenser aiming to validate the capillary performances of the flexible joint. All the results are compared with the same AGHP profile extruded heat pipes and demonstrate an impact on overall performances of the developed flexible technology lower than 10% for the heat transport capacity and no impact on the heat transfer coefficients. The maturity is TRL5/6 at the end of this activity.