Two-Dimensional Numerical Analysis of Boiling Two-Phase Flow of Liquid Helium

The two-dimensional characteristics of the boiling two-phase flow of liquid helium in a duct are numerically investigated to realize the further development and high performance of new cryogenic engineering applications. First, the governing equations of the boiling two-phase flow of liquid helium based on the unsteady drift-flux model are presented and several flow characteristics are numerically calculated, taking into account the effect of superfluidity. Based on the numerical results, the two-dimensional structure of the boiling two-phase flow of liquid helium is shown in detail, and it is found that the vapor gas phase rapidly spreads throughout the inner flow duct because of the change of the pressure gradient due to the effect of superfluidity which appears in momentum equations. Next, it is clarified that the distributions of the void fraction, the velocity field and the instantaneous streamline of two-phase superfluid helium flow show a tendency different from those of normal fluid helium because the counterflow of two-phase superfluid occurs against normal fluid flow. According to these theoretical results, the fundamental characteristics of the cryogenic boiling two-phase flow are predicted. The numerical results obtained would contribute to advanced cryogenic industrial applications.