No abstract

A moving-boundary model of two-phase cryogenic flow, which was developed in the companion paper (Hafiychuk, V., Foygel, M., Ponizovskaya-Devine, E., Smelyanskiy, V., Watson, M., Brown, B., and Goodrich, C., "Moving-Boundary Model of Cryogenic Fuel Loading, I: Two-Phase Flow in a Long Pipe," Journal of Thermophysics and Heat Transfer (to be published)), is applied toward simulation of liquid nitrogen flow data collected for the cooldown regime in two different experimental fuel transfer lines: 1) the 1966 National Bureau of Standards (now the National Institute of Standards and Technology) setup and 2) the novel NASA Kennedy Space Center cryogenic testbed. With relatively small computational effort compared to full-scale schemes, the model describes pressure and temperature histories, kinetics of the vapor void fraction, and interphase boundary motion in two different parts of the transfer lines. The aforementioned time-dependent characteristics are shown to be in a good agreement with the experimental data on the cooldown stage of liquid nitrogen loading obtained at the National Bureau of Standards setup (with no fitting parameters used) and in a fair agreement with the NASA Kennedy Space Center testbed setup (with a small fitting) for chilldown and fast fill operations. The fast and accurate modeling procedure accounts for cryogen fueling operations in both the nominal and major fault regimes. Nomenclature A = internal cross-sectional area of pipe, nozzle, or vent valve, m 2 C = constant pressure (volume) specific heat, J∕K∕kg D = diameter of pipe, m t = time, s κ = thermal conductivity, W∕m · K ρ = density, kg∕m 3Subscripts O = outer vent = vent w = tube wall

We consider problem of modeling and controlling two-phase cryogenic flows during ground loading operations. We introduce homogeneous moving front and separated two-phase flow solvers that are capable of fast and accurate online predictions of flow dynamics during chilldown and transfer under nominal conditions and in the presence of faults. Concise sets of cryogenic correlations are proposed in each case. We present results of application of proposed solvers to the analysis of chilldown in large-scale experimental cryogenic transfer line build in Kennedy Space Center. We discuss optimization of parameters of cryogenic models obtained using general inferential framework and an application of the solvers to the fault detection and evaluation based on D-matrix approach. It is shown that solver's predictions are in good agreement with experimental data obtained for liquid nitrogen flow in nominal regime and in the presence of faults.