Evaluation of Recirculation Time in Bubble Train Flow by Using Direct Numerical Simulation

In this research, hydrodynamics of the Bubble Train Flows (BTF) in circular capillaries has been investigated by Direct Numerical Simulation (DNS).The Volume of Fluid Based (VOF) interface tracking method and streamwise direction periodic boundary conditions has been applied. The results show that there exists an appropriate agreement between DNS and experimental correlation results. The recirculation time as an important parameter, which affects the mass transfer of gasliquid slug flow through the capillaries channel, has been calculated. The effects of different parameters such as capillary length, capillary diameter, unit cell length, and surface tension on recirculation time have been investigated. Afterwards, the DNS based correlation has been proposed for BTF recirculation time in a circular capillary