Lagrangian simulation of bubbly flow
Accurate prediction of the multidimensional bubble motion in bubbly two-phase flow is required in various industrial applications. For instance, since the condensation rate is dependent on the lateral phase distribution in subcooled flow boiling, sufficient knowledge on the lateral bubble migration from the heating surface toward the subcooled bulk liquid is indispensable for accurately predicting the net vaporization rate and also the axial development of void fraction. One-dimensional calculation is widely performed in the simulation of two-phase flow but the conventional one-dimensional two-phase flow models would not be sufficient to analyze the lateral void distribution in a mechanistic way. Thus, an Eulerian-Lagrangian model, in which the motion of each bubble is individually tracked, is adopted here since more detailed modeling of multidimensional bubble motion is possible comparing with the fully-averaged two-fluid model. The predicted lateral void profiles are extensively compared with experimental data in wide ranges of liquid velocity and bubble size in order to test the validity of the constitutive models.
Expected bubble behavior in turbulent pipe flow