Numerical study on helium condensation in supersonic nozzles of various structures.

This study innovatively applies Supersonic Two-Phase Expander to the helium liquefaction process. In order to illustrate the spontaneous condensation of helium, this work describes the construction of a numerical model, the accuracy of which is verified by both Moses and Wyslouzil nozzles. Simulation results indicate that lengthening the convergent section from 0.13385 m to 0.16385 m enhances the outlet liquid mass fraction from 14.502 % to 14.896 % and raises the zenith nucleation rate from 6.350 × 1019 m􀀀 3⋅s􀀀 1 to 8.371 × 1019 m􀀀 3⋅s􀀀 1. When the expansion angle of the divergent section is raised from 2.4◦ to 3.2◦, the outlet temperature shows a reduction from 3.072 K to 2.766 K, whereas the outlet liquid fraction grows from 13.381 % to 14.953 %. The findings elucidate that lengthening the convergent section and increasing the expansion angle can facilitate helium condensation, which is fundamental to the design of the swirling nozzle.