Substitute Mixtures for Lox Droplet Vaporization Study

Recent numerical works were concerned with vaporization of O2-H2 cryogenic mixture, i.e. liquid oxygen (LOX) droplets surrounded by gaseous hydrogen. These different approaches are subject to large uncertainties concerning transport modelings in dense gas. Because no experimental data can arbitrate the rather scattered set of predictions, the purpose of the present work is to numerically study the behaviour of three binary mixtures, namely O2-He, O2-N2 and N2-H2 that can form the subject of “safe” experiments and to suggest eventual substitutes for the O2H2 couple Using the O2-N2 mixture leads to vaporization processes qualitatively different from the expected ones for the O2-H2 couple. In other words, no subcritical vaporization can be obtained above the critical pressure of oxygen. Substitution of helium for hydrogen can however provide such a behaviour and quantitative comparison shows that O2-He is a relevant substitute. Actually, substituting liquid nitrogen for liquid oxygen seems to be the best way to obtain correct data for the O2-H2 cryogenic mixture. It is then possible to make identical vaporization processes for both mixtures (O2-H2 and N2-H2) provided that the results are analysed in a relevant reduced form which depends on the vaporization regime (subcritical or supercritical).