2 DIMENSIONAL MODEL ANALYSIS OF FLOW BEHAVIOR OF HIGHLY VISCOUS NON-NEWTONIAN FLUID IN AGITATED VESSEL WITH PADDLE IMPELLER

A flow of non-Newtonian power law fluid in an agitated vessel with paddle impeller is obtained from numerical analysis based on a two dimensional flow model. The average shear rate obtained from the numerical solution coincides well with the experimental result for large-size impeller of d/D>0.7, and it is confirmed that the apparent viscosity is very useful in correlating not only power input but also shear stress distribution at vessel wall. The non-Newtonian viscosity profile in an agitated vessel depends remarkably on impeller dimension and scarcely at all on vessel dimension. This shows the usefulness of the concept of apparent viscosity proposed by Metzner et ah On the other hand, the velocity and vorticity profiles near the vessel wall can hardly be correlated with the characteristic velocity alone, because the flow pattern depends on the integrated effect of non-Newtonian viscosity in. © 1979, The Society of Chemical Engineers, Japan. All rights reserved.