Effects of Particle Density on Gas-Liquid-Solid Flows in Bubble Columns

A numerical simulation is performed to study the effects of particle density on gas-liquid-solid flows in bubble columns. An Eulerian-Lagrangian model is used where the liquid flow is modeled by a volume-averaged system of governing equations and motions of particles and bubbles are modeled by Lagrangian trajectory method. Interactions between particle-particle, bubble-bubble, bubble-liquid and particle-liquid are included in the study. The drag, lift, buoyancy, and virtual mass forces are evaluated for the particles and bubbles. Particle-particle and bubble-bubble interactions are accounted for by a hard sphere model. The bubble coalescence is also included in this study. The predicted results were compared with the experimental data in a previous work, and satisfied agreement was obtained. Particles with various density are used in different cases. A parcel method is used to account for particle load. The effects of particle density on gas-liquid-solid three-phase flows are discussed based on the comparison of the transient flow characteristics of these gas-liquid-solid three-phase flows. The simulations show that large particle density may result in weak phase mixing in gas-liquid-solid three-phase flows in bubble columns.