Collect. Czech. Chem. Commun. 1987, 52, 1416-1429

Description of the flow of mechanically agitated liquid in a system with cylindrical draft-tube and radial baffles

Ivan Fořta, Miloslav Hošťálekb, Hans Dietrich Laufhüttec and Alfons Bertram Mersmannc

a Department of Chemical and Food Process Equipment Design, Czech Technical University, 166 07 Prague 6, Czechoslovakia
b Chemopetrol – Research Institute of Inorganic Chemistry, 400 60 Ústí nad Labem, Czechoslovakia
c Lehrstuhl B für Verfahrenstechnik, Technische Universität München, 8000 München 2, F.R.G.


A model is described of two-dimensional vortex turbulent flow of homogeneous liquid in a cylindrical tank with flat bottom and radial baffles at its walls agitated with an inclined plane blade impeller rotating in a cylindrical draft-tube. The obtained field of the mean Stokes stream function expresses the streamline distribution in the system. As the boundary conditions of the used solution of stream equation serve partly the values of the mean Stokes stream function on the system boundaries (bottom, liquid level, walls of tank and draft-tube, tank axis), partly the radial profiles of axial and radial components of mean velocity on the level of draft-tube lower base obtained by the laser-doppler anemometry. It follows from the comparison with results of previously published studies that in systems with cylindrical draft-tube and axial high-speed impeller, the convective flow intensity of agitated liquid is higher and the streamline distribution in system is more uniform providing that the conical bottom with 120° vertex angle is used instead of the flat bottom.