CFD simulation of precipitation in the sliding-surface mixing device

Steady-state precipitation of pseudo-boehmite is studied in the sliding-sur face mixing device, both experimentally and using a commercially available CFD package (FLUENT (R) 4.5). A 3-D description of the reactor geometry is employed. Solutions of the Navier-Stokes equations along with the standard two-equation k-epsilon turbulence model provide both the velocity and energ y dissipation fields, while generation and development of the solid crystal phase are described by the moment equations of the population balance. The se equations and the precipitation kinetics have been implemented directly in the CFD code using Fortran User-Defined Subroutines. A size-dependent gr owth rate model is used to describe the crystal growth of pseudo-boehmite c rystallites. Local quantities are calculated, such as species concentration s, supersaturation and mean particle size. A good agreement is obtained bet ween experimental and predicted crystal properties. The influence of feed p oint location, rotating speed of the spinning disk and reagent concentratio ns on the duality of the precipitate is also investigated. (C) 2001 Elsevie r Science Ltd. All rights reserved.