Friction reduction degradation in dilute poly(ethylene oxide) solutions

Abstract

Abstract Degradation of friction‐reducing effectiveness of dilute poly(ethylene oxide) solutions subjected to continuous agitation is examined in disk flow. A residual or steady‐state effectiveness is observed which disappears only at a sufficiently high Reynolds number. The onset of friction reduction appears to occur within the transition region and seems to be independent of solution concentration. The onset of degradation also appears to be independent of concentration. Prior shear working is shown to have a significant effect on residual friction‐reducing effectiveness only when the shear working is performed in a more intense shear field than that in which the friction‐reducing effectiveness is evaluated. Degradation of friction‐reducing effectiveness is compared to corresponding changes in viscosity‐average molecular weight. The experimental results are interpreted in terms of a model of the interaction between polymer molecules and the turbulent flow field.