Modeling Turbulence Effects in Cryogenic Propellant Tank Thermal Management

Control and management of cryogenic propellant tank pressures in low gravity is an important technical challenge to overcome for future long duration space missions. Advanced techniques such as thermodynamic vent systems (TVS) are currently being designed for low-gravity space systems, and advanced computational tools are required to analyze the complex multi-phase physics involved. The proposed effort extends computational fluid dynamics capabilities to consider the behavior and effects of turbulence on heat/mass transfer at the tank gas/liquid interface and dispersed-phase droplet vaporization. Model extensions to fundamental kinetics-based mass transfer models are investigated for application to cryogenic systems. The methodology will be tested with the CRUNCH CFD code which incorporates real-fluid equations-of-state for cryogenic fluid mixtures with rigorous fluid property definitions, and an advanced dispersed phase spray model that permits non-equilibrium mass, drag, and heat transfer with the surrounding continuum fluid. The models improvements will be readily transferable to alternate codes and support unsteady RANS simulations in an Eulerian-based gas/liquid framework. This technology will support cryogenic system analysis for long duration space exploration activities.