Some analytical tools for fluids management in space: Isothermal capillary flows along interior corners

Abstract

Recent advances in the analysis of a class of capillary-driven flows relevant to materials processing and general fluids management in space have been made. The class of flows addressed concern spontaneous capillary flows in complex containers with interior comers. Such flows are commonplace in space-based fluid systems and arise from the particular container geometry and wetting properties of the system. Important applications for this work involve low-g liquid fill and drain operations where the container geometry is complex, possessing interior corners, and where quantitative information of fluid location, transients, flow rates, and stability is critical. Examples include the storage and handling of liquid propellants and cryogens, water conditioning for life support, fluid phase-change thermal systems for temperature control and power production, materials processing in the liquid state, and on-orbit biofluids processing. For several important problems, closed-form expressions to transient three-dimensional flows are possible that, as design tools, compliment if not replace difficult, time-consuming, and rarely performed numerical calculations. The theory is readily extended to address more complex flows. An overview of a selection of solutions in-hand is presented. Drop tower and low-g aircraft experimental results are cited to support the theoretical findings.