Design Validation - via Parabolic Flight Tests - of a Condensate Buffer Equalizing a Discontinuous Gas / Water Flow between a Condensing Heat Exchanger and a Water Separator

EADS SPACE Transportation GmbH designed, built and tested a condensate buffer to be located between a Condensing Heat Exchanger (CHX) and a Condensate Water Separator Assembly (CWSA), as part of the ECLSS of the European Columbus Module. Under zero-g conditions the separation of water from an air-water mixture is always difficult, especially if a passive (or low power consuming as the Columbus CWSA) device is to be used. The additional buffer volume shall reduce condensate water peaks reaching the CWSA to a level that excludes an overloading of the CWSA and a release of free water droplets into the air return to the cabin. In the CHX/CWSA system this may only be necessary under worst case operational conditions and with a failure of the qualified hydrophilic coating of the CHX. The buffer design principle was confirmed via prior analyses and on-ground testing. The performance of such a condensate buffer under micro-g conditions was verified during parabolic flights. The tests were conducted with Plexiglas models to observe how the separated water behaves in the buffer volume under micro-g conditions. Based on the results of the parabolic flight campaigns, the design of the condensate buffer is baselined for potential application in the ISS Columbus module as part of its ECLSS. The achievements may also support the optimization of any other kind of discontinuous gas/liquid separation under micro-g conditions.