CFD modelling of polydisperse flows in horizontal pipes

Accurate CFD modelling of gas/liquid, liquid/liquid polidisperse flows requires two key models: (i) turbulent dispersion of bubbles (droplets) in order to produce correct vertical distribution of the dispersed phase and (ii) population balance in order to account for the polidisperse nature of the flow. In the present work we use the A-MuSiG method implemented in STAR-CCM+CFD code of CD-adapco. The dispersed phase is split into M size groups having their own velocities. Size of a group is not prescribed a priori, but calculated from an additional scalar equation. Balance of the turbulent dispersion and buoyancy forces induces a secondary recirculation of the bubbles in the transverse section of the pipe. Different bubble size have different velocities what has a significant implications for the mixing in the transversal direction.