Numerical simulation of upward microbubble-laden turbulent channel flow

To improve the predictive accuracy of bubble concentration distribution, numerical study of upward turbulent channel flows laden with microbubbles is carried out and the fluid-bubble two-way coupling interaction is considered. Direct numerical simulation is used for solving the Navier-Stokes equation and Lagrangian approach is used to track the bubble trajectories through the action of forces imposed by the fluid and the gravity. The forces acted on the bubbles are drag, virtual mass, lift, wall lift, pressure gradient, and gravity. Numerical results show that the bubble concentration distribution can be predicted by using the two-way coupling of the fluid and the bubble motion, and adding the wall lift force into the bubble motion equation, and the fluid velocity, turbulence intensity and shear stresses modified by the bubble motions can also be revealed.