METHOD OF FILLING SCREEN LIQUID ACQUISITION DEVICES IN LOW GRAVITY

This work addresses the problem of filling screen-channel liquid acqui sition devices in very low gravity. The concept of using a thermodynam ic vent system to promote Clapeyron pumping and condensation is propos ed in two configurations, a triangular apex-mounted heat exchanger and a concentric cylinder heat exchanger. The performance of the concept in low gravity is then evaluated by analysis. By approximating the liq uid surfaces as flat and parallel, the triangular configuration is rel ated to the cylindrical configuration. Results of a numerical solution to the one-dimensional cylindrical heat-transfer problem showed that a quasi-steady analytical solution suffices for the Jakob numbers of i nterest. For an initially empty, channel of 38-cm(2) cross-sectional a rea with a 10:1 ratio of channel height to heat exchanger radius, and 4-K Joule-Thomson expansion, complete fill occurs in 30 min. The conce pt was then proven by testing performed in 1g with Freon-114 at Jakob numbers similar to that in a hydrogen, on-orbit servicing environment. A screen-channel test article was successfully filled against gravity . This reliable method of filling screen channels enables on-orbit res upply of space-based systems that must deliver liquid in low gravity, such as a fuel depot.