Numerical and Experimental Study of Liquid Cryogenic Jet around a Space Plane and Its Ignition Risk

Ariane Group is currently developing space vehicles using new LOx/LCH4 propulsion technology. Venting or draining out methane from the tanks in flight at various altitudes concerns the safety management. This paper is focusing on the modeling of liquid methane draining around a moving space plane. A cryogenic round jet in an air crossflow has to be considered. However, the computational cost for a vaporizing liquid jet model is too high with respect to the goals of the study. A more time-friendly densified gas model has thus been developed. Experiments on liquid nitrogen were conducted to validate the numerical results. Numerical and experimental jet trajectories are in the same order of magnitude. Liquid column height is also properly modeled. The model is thus validated for pre-study calculations where global behaviors need to be determined without a prohibitive cost.