EFFECTS OF NEUTRALLY BUOYANT PARTICLES ON GAS-LIQUID-SOLID FLOWS

摘要

A numerical study is carried out to investigate the effects of neutrally buoyant particles on gas-liquid-solid flows in bubble columns. An Eulerian-Lagrangian model is used, where the liquid flow is modeled using a volume-averaged system of governing equations, while motions of bubbles and particles are evaluated using Lagrangian trajectory approach. The bubbles are assumed to remain spherical in the simulation. Bubble-liquid interaction and particle-liquid interaction are included in the study. The drag, lift, buoyancy, and virtual mass forces are included for the discrete phases. Particle-particle interactions and bubble-bubble interactions are simulated using a hard sphere model. Bubble coalescence is also included in the analysis. Neutrally buoyant particles are used in the study. A parcel approach is used where a parcel represents a certain number of particles of the same size, velocity, and other properties. The predicted results were compared with the experimental data in a previous work, and the oscillation of the bubble plume was successfully predicted. The transient flow characteristics of a gas-liquid-solid three-phase flow with a particle volume loading of 6% and a gas-liquid two-phase flow are studied and the effects of neutrally buoyant particles are discussed. The simulations show that the presence of particles can affect the characteristics of the flows and the case without particles leads to a less oscillatory flow.