CFD Modeling of Solid Suspension in a Stirred Tank: Effect of Drag Models and Turbulent Dispersion on Cloud Height - Application Brief

Many chemical engineering processes involve the suspension of solid particles in a liquid, with the goal being homogeneous particle distribution. When the solid particle loading is high, agitation forms a clear liquid layer above a cloud of dispersed solids. Cloud height, defined by the location of the cloud/clear-liquid interface, is a critical measure of mixing efficiency. In this study, solid–liquid mixing experiments were conducted, and cloud height was measured as a function of operating conditions and stirred tank configuration. Computational fluid dynamics simulations were then performed using a multiphase model. The effects of hindered and unhindered drag models and turbulent dispersion forces on cloud height were investigated, showing excellent agreement between experimental and computational data over the full range of testing conditions.