Development and Tests of a Loop Heat Pipe Capillary Blocker using Additive Layer Manufacturing

The goal of the present study was to develop a specific device, inserted inside a multi-condenser Loop Heat Pipe (LHP), that enables the liquid flow from an active condenser, while blocking the vapor from an inactive condenser, in order to maximize the use of available radiating surfaces on a Spacecraft. The retained concept was to use a porous medium, to take benefit of the induced capillary forces. A first capillary blocker prototype was developed by inserting a PTFE porous wick, with a specific design, inside a standard T-junction downstream the condensers. Thermal Vacuum tests on a dual-condenser LHP proved that the capillary blocker was working properly. An optimized prototype was then developed using Additive Layer Manufacturing. This monolithic capillary blocker underwent mechanical tests, which did not affect its integrity, as well as Thermal Vacuum tests, which validated its correct operation.