Numerical analysis of the onset of droplet entrainment in annular two-phase flow by hybrid method

A particle-grid hybrid method for simulating the onset of droplet entrainment is described. The air and liquid phases are expressed by grid and particle separately. The effects of surface tension and wall adhesion are calculated by the continuum surface force model. The fluid film variation and the droplet disengaging process are analyzed. The onset of entrainment criterion is obtained which has a good agreement with the correlation of Ishii and Grolmes (AIChE J., 21, 308-318). The influences of surface tension and gas phase density on the criterion are also studied. Several simulation flow fields are given for illustrating the efficiency of the method.