Pipe Flows of Dilute Aquwous Polymer Solution : Part 2, Correlation of the Frictional Characteristics

Abstract

A correlation of the frictional characteristics of dilute polymer solutions is established from the measurements of the velocity profile. The difference of profile from Newtonian fluids is found in the buffer layer. Analysis is made with much attention paid to the difference of the buffer layer. It is assumed that the Toms effect occurs only in the region, in which the shear rate is larger than the critical shear rate γ^*. This critical shear rate γ^* is dependent on the concentration and the heading tank level under certain condition. Comparisons of the analytical results with the experimental results are made for two different pipe-sizes using solutions of 3.5 to 35 wppm. The results show : 1) Such parameters as the concentration, pipe diameter or heading tank water level have influence on the Toms effect only in unsaturated regions of the Toms effect ; and 2) the pipe size which will be used for the model test to predict the characteristics in a large pipe is limited by γ^*.