Validation of Stanton Number Correlation for Jet Mixing and Its Extension to Microgravity

Cryogenic propellants provide high energy density but introduce operational challenges due to boil-off, self-pressurization, and vapor flashing during transfer. The No-Vent Fill (NVF) technique mitigates these issues by controlling tank pressure and enabling efficient vapor condensation in the ullage region. During NVF, a high-velocity submerged jet drives vigorous internal mixing, which significantly enhances condensation at the liquid–vapor interface. Existing correlations for interface heat and mass transfer, however, were developed under 1-g conditions and possess uncertain applicability to low-gravity environments. In this study, vapor condensation driven by an axial turbulent jet was numerically investigated using Loci/STREAM-VOF. The area-averaged interfacial root-mean-square (RMS) turbulence velocity was computed and incorporated into the correlation of Brown et al. (1990). The model was validated against available 1-g condensation data. The CFD results reproduced both the fill-level dependence and the tank-size dependence documented experimentally, confirming the validity of the turbulence–condensation framework. The applicability of the Stanton number correlation to low-gravity jet-mixing conditions is investigated, and its behavior is assessed through parametric simulations.