ANOTHER LOOK AT THE MIXING PROCESS

Comprehensive theoretical-numerical investigations of flow phenomena a nd the homogenization of miscible fluids in conventional mixing vessel s have been carried out. It has been verified that more than 80% of th e energy transferred to the fluid remains in the primary motion and on ly less than 20% is transferred onto the secondary motion. In homogeni zation processes it is the secondary flow only that contributes to mix ing. A detailed analysis of the development Of the concentration field in the fluid revealed that the mixing process may be divided in three steps: 1) convective transport of fluid A by the jet stream resulting from centrifugal forces to the vessel wall in the plane of the stirre r, 2) convective transport of fluid A by the vortices of secondary flo w, 3) molecular transport of fluid A when the field of lines of consta nt concentration approaches identity with the field of stream lines. F rom the results of this investigation conclusions have been drawn usef ul for improvement of technical mixing systems.