At the HYPER Laboratory, we conduct both reduced-order modeling (ROM) and high-fidelity computational fluid dynamics (CFD) simulations of thermofluid processes and systems with liquid hydrogen, including LH2 storage tanks, Taconis phenomena, phase-changing hydrogen flows, ortho-parahydrogen conversion, and cryocooling. A few examples of our studies are given in this section.
A lumped-element model has been developed for stationary LH2 storage tanks to analyze self-pressurization, venting, and passive and active cooling, including zero boil-off methods. A general schematic of a tank is shown in Fig. 1. The governing energy and mass conservation equations are formulated for the liquid and ullage domains, and empirical correlations are applied for heat and mass transfer rates. An example of a validation study using test data available for NASA multipurpose hydrogen test bed (MHTB) is illustrated in Fig. 2. Time-dependent modeling results of self-pressurization and constant-pressure venting in tanks of different sizes are given in Figs. 3 and 4, showing advantage of large tanks with large volume-to-surface ratio.
We also employ state-of-the-art CFD tools to carry out detailed (but computationally expensive) modeling of various processes involving liquid hydrogen. A video below shows (1) LH2 tank sloshing, (2) initial stage of self-pressurization and thermal stratification in LH2 tank, (3) tank filling with LH2, and (4) attainment of the choked regime in phase-changing LH2 flow through a nozzle.