CFD-PBM MODELING OF VERTICAL BUBBLY FLOWS

A 3-D Eulerian-Eulerian multiphase Computational Fluid Dynamics (CFD) model combined with Population Balance Modeling (PBM) were presented for two phase bubbly flow in vertical pipes. The discrete bubble sizes prescribed in the dispersed phase were tracked by solving an additional set of transport equations, which these equations were progressively coupled with the flow equations during the simulations. Important flow quantities such as local void fraction, liquid velocity and normal turbulent stresses were calculated and compared against experimental data from literature. Good agreement with the experimental data was obtained. It was found that void fraction profile exhibited a sharp peak near the wall. The liquid velocity profile was flattened by the presence of the vapor phase (i.e. the bubbles), and all three normal fluctuations were affected by the presence of the vapor phase. These fluctuations do not increase monotonically as the void fraction increases. Thus this CFD-PBM modeling can be used for prediction of wall peaking and coring phenomena, and radial void distribution.