Two-Dimensional Numerical Analysis on Boiling Two Phase Flow of Liqiud Helium

Abstract

Two-dimensional characteristics of boiling two-phase flow of liquid helium in a duct flow are numerically investigated to realize the further development and high performance of new cryogenic enginering applications. First, the governing equations of 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 term. Based on the numerical results, the two-dimensional structure of boiling two-phase flow of liquid helium is shown in detail, and it is found that the vapor gas phase strongly spreads throughout to the inner flow duct because of the change of pressure gradient due to the effect of superfluidity which appears in the momentum equations. Next, it is clarified that the distribution of the void fraction, velocity field and instantaneous streamline of two-phase superfluid helium flow show quite a different tendency from that of normalfiuid helium because the counter flow of two-phase superfluid occurs against to the normalfiuid flow. According to these theoretical results, it seems reasonable to predict the fundamental characteristics of cryogenic boiling two-phase flow. The numerical results obtained should contribute to advanced cryogenic industrial applications.