EFFICIENT SIMULATION OF A TWO-PHASE VERTICAL PIPE FLOW WITH POPULATION BALANCE METHOD

The population balance equation for bubble size distribution in a vertical turbulent pipe flow is solved with a Direct Quadrature Method of Moment (DQMOM) comparing the results with a classical approach where bubbles are characterized by their mean size. The turbulent two-phase flow field, solved within a RANS formulation, is assumed to be in local equilibrium and the relative gas and liquid velocities are therefore calculated with an algebraic slip model, considering drag and lift forces. The non-linear relation between the bubble size and the resulting forces is accurately described through the DQMOM method, in which each quadrature node represents a dynamic class of particles with a characteristic size. Results are compared to experimental results (Szalinski et al., 2010), demonstrating that fast and accurate predictions are obtained for the void fraction and the bubble size distribution in the case of moderate bubble Stokes number and void fraction.