Analytic characterization and operational limits of a hybrid two-phase mechanically pumped fluid loop based on the capillary pumped loop

Abstract

Two-phase mechanically pumped fluid loops have the potential to provide numerous benefits for spacecraft based applications. Here a hybrid two-phase capillary and mechanically pumped fluid loop that shows promise for spacecraft thermal control applications is analyzed and its operational limits are characterized. Data from an experimental system that incorporates a 3D printed evaporator is correlated to several models that together provide a comprehensive characterization of the system behavior. The loop performance is analyzed using pointwise as well volume-averaged governing equations and resistance network models, to predict flooding and dryout limits. Also, system-level numerical (including 3-D CFD simulations) transient and linear-response analyses are performed predicting the changing loop phase distributions and the observed time-dependent behavior. With the 3D-printed evaporator, a notably high evaporator conductance of 30 W/cm2-K and heat flux over 10 W/cm2 over large area are achieved with negligible temperature non-uniformity.