Validation of Pressure Control in a Flight-scale Liquid Hydrogen Tank using a Spray Bar

Cryogenic fluid management (CFM) is one of the fundamental technologies required to support the National Aeronautics and Space Administration (NASA)’s Moon and Mars human landing missions. One of the propellant tank pressure control technique leverages liquid spray injection in the tank ullage to depressurize the tank. Flight-scale ground tests of spray bar depressurization were conducted at NASA Marshall Space Flight Center using the multi-purpose hydrogen test bed (MHTB) tank. One of the test is validated using computational fluid dynamics (CFD). Liquid spray is modeled in Loci-Stream CFD solver using Lagrangian particle transport (LPT), which is two-way coupled with the Eulerian simulation with well-established Eulerian-Lagrangian mass, momentum, and energy coupling models. Droplet and Eulerian gas-liquid interface both have phase change capabilities that include thermal equilibrium model and Hertz-Knudsen-Schrage model. A well-established asymmetric turbulence transport model was also employed to achieve accurate phase change prediction at the Eulerian two-phase interface. A Weber number based droplet breakup and coalescence/scattering model was also used to predict physically accurate mass/momentum/energy transfer between the Eulerian and Lagrangian fluids. Improved delayed detached eddy simulation (IDDES) along with Menter’s SST modeling technique reliably modeled the turbulence. A successful, and parameter-free validation against flight-scale tank test builds further confidence in use of Loci-Stream CFD solver and described modeling techniques for CFM modeling for human spaceflight projects.