Numerical modelling the influence of gas distributors on gas-liquid flow and mixing in a bubble column

摘要

Numerical simulations of gas-liquid flow in a cylindrical bubble column of 400mm with two-fluid approach and MUSIG model were conducted at high superficial gas velocity Ug=0.10m/s for eight gas distributors to investigate the influence of sparger designs on hydrodynamic, gas hold-up, mixing, turbulence and mixing time. The simulation results showed that the effect of sparger designs on liquid velocity and local gas holdup are significant in the sparger region. The comprehensive comparison of gas-liquid interfacial area and mixing time shows that the none of the considered spargers could not only produce the highest interfacial area but also yields the shortest mixing time. The modelling results also suggest that the more gas pipes are beneficial to increase the gas hold-up but harmful to reduce bubble size due to decreasing of turbulent kinetic dissipation,the asymmetrical structure and smaller circle diameter of gas pipes are profitable to enhance liquid mixing.