One-dimensional drift-flux model at reduced gravity conditions

The drift-flux model is of practical importance for two-phase flow analyses at reduced gravity conditions. In view of this, the drift-flux model, which takes the gravity effect into account, is studied in detail. The constitutive equation of the distribution parameter for bubbly flow, which takes the gravity effect into account, has been proposed, and the constitutive equations for slug, churn, and annular flows, which can be applicable to reduced gravity conditions, are recommended based on existing experimental and analytical studies. The previously derived constitutive equations of the drift velocity in various two-phase flow regimes, which takes the frictional pressure loss into account, are adopted in this study. A comparison of the model with various experimental data over various flow regimes and a wide range of How parameters taken at microgravity conditions shows a satisfactory agreement. The drift-flux model has been applied to reduced gravity conditions such as 1.62 and 3.71 m/s(2), which correspond to the lunar and Martian surface gravities, respectively, and the effect of the gravity on the void fraction in two-phase flow systems has been discussed.