Three-dimensional CFD–VOF–DPM simulations of effects of low-holdup particles on single-nozzle bubbling behavior in gas–liquid–solid systems

Three-dimensional (3D) computational fluid dynamics (CFD) simulations of effects of low-holdup solid particles on the bubbling behavior in a gas–liquid–solid flow system with single gas nozzle were performed with discrete particle model (DPM) and volume of fluid (VOF) method. Both gas and liquid phases (Eulerian phases) were modeled using a continuity equation and a set of momentum equations and the interface of the gas bubbles were tracked using the VOF model. The Lagrangian particles were linked to the Eulerian phases through the interchange terms such as the drag force in the respective momentum equations. Influences of particle properties including volume fraction, diameter and density, fluid properties including liquid surface tension force and viscosity, operating conditions including nozzle gas velocity, superficial liquid velocity, and wettability of gas nozzle material on the size, detachment time and rise velocity of gas bubbles and particle entrainment in the gas–liquid–solid flow under ambient conditions were numerically investigated and the trends analyses were done using related dimensionless numbers. The work lays a foundation for further explorations on the gas–liquid–solid flows and possible industry applications.

Graphical abstractThree-dimensional numerical simulations of effects of solid particles with very low holdup on the bubbling dynamics in a gas–liquid bubble column with single gas nozzle were performed with coupled discrete particle model and volume of fluid method. The influences of particle properties including the number, size and density, operating conditions including nozzle gas velocity, superficial liquid velocity, fluid properties including liquid surface tension force and viscosity, and wettability of nozzle material on gas bubble diameter, detachment time and rise velocity in the gas–liquid–solid flow under ambient condition including particle entrainment were numerically investigated. Simulations agree well with experiments.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Effect of suspended particles on 3D single-nozzle bubbling process was simulated by CFD–VOF–DPM model. ► Trends of single-nozzle bubbling dynamics with factors in gas–liquid–solid flows were obtained. ► Wettability of nozzle materials on bubbling behavior in the gas–liquid–solid flow was studied. ► 3D particle entrainment in the gas–liquid–solid flow was simulated. ► Local mesh refinement was used to get good simulations with limited computational resource.