Cryogenic Fuel Management

Why it matters

Liquid hydrogen (LH₂) and liquid methane (LCH₄) are central to long-duration spaceflight and to the emerging hydrogen economy. Both are stored close to their boiling points, so small heat leaks cause boil-off, pressure rise, and propellant loss. Designing tanks, transfer lines, and venting systems depends on knowing how fast these fluids evaporate and condense at the liquid–vapor interface. Those rates are hard to measure, and published values for the key kinetic parameter (the accommodation coefficient) span several orders of magnitude.

Our approach

• Cryo-neutron experiments. Neutrons pass through aluminum and stainless steel but are strongly attenuated by hydrogen, so neutron imaging can show a cryogenic meniscus inside a sealed metal cell. We designed and ran a series of experiments that image evaporation and condensation of LH₂ and LCH₄ in real time, and measured contact angles and wettability at cryogenic conditions.
• Transient thermal modeling. The experimental cell’s wall temperature field is reconstructed with transient conduction models, which provides the boundary conditions that interface-scale models need.
• Coefficient-free evaporation modeling. We combine kinetic theory, thin-film physics, and CFD so that evaporation rates can be predicted instead of tuned to match data. This work (led by Ayaaz Yasin) includes a multiscale CFD model of evaporating hydrogen menisci that carries subgrid thin-film dynamics and in situ accommodation coefficients.

Selected outcomes

• An open, publicly archived dataset of LH₂/LCH₄ phase change experiments (Data in Brief, 2022)
• Cryogenics Best Paper Award (2022)
• Computational Modeling of Evaporation without Tuning Coefficients, Applied Thermal Engineering (2025)
• A Multiscale CFD Model of Evaporating Hydrogen Menisci, Fuels (2026)
• Talks at the Space Cryogenics Workshop, NASA TFAWS, APS-DFD, ASTFE, and the Gordon Research Conference

Broader relevance

The same physics governs cryogenic processing wherever a liquid–vapor interface meets a solid at low temperature: propellant depots, hydrogen storage and transfer, cryogenic cooling of equipment, and cryogenic steps in advanced manufacturing.