NUMERICAL-ANALYSIS ON FLOW BEHAVIOR OF BINGHAM FLUID IN AN ANCHOR IMPELLER MIXER

Three-dimensional flow of Bingham fluid in an anchor impeller mixer was numerically analysed. The basic equations were composed of the equation of continuity, the equation of motion and the model equation representing rheological characteristics of Bingham fluid. The analysis was performed by the FDM method. An empirical technique was investigated to obtain the analysis with stable solution using a vessel with coaxial cylinder, in which the flow behaviour can be analytically calculated. This technique was applied to the anchor impeller mixer. Consequently, the characteristic velocity distribution of the fluid could be quantitatively determined. The apparent viscosity of the liquid was also found to have lower values in the vicinity of the impeller and to increase rapidly with increasing distance from the impeller. The reliability of this method was confirmed by the good agreement between the numerical results and the experimental data obtained for the free surface of the slurry in the mixer. © 1990, The Society of Chemical Engineers, Japan. All rights reserved.