Effect of Polymer Coiling on Drag Reduction

摘要

Tube flow data indicate that the drag reduction of high molecular weight polymer solutions decreases in an orderly fashion with inc.eased molecular coiling of the polymer. A correlating equation for this effect is presented. For three polymers at four concentrations the maximum drag reduction was obtained at temperatures less than 105F and at 140F solutions of all three polymers suffered a decrease in drag reduction. A graphical relationship is presented that qualitatively correlates the variation of viscosity and drag reduction caused by a variation in temperature. A decrease in drag reduction occurs if low concentration of high molecular weight polymers are subjected to steady state turbulent tube flow. A slow decrease in viscosity of high molecular weight solutions due to physical adsorption on the solid surfaces in glassware as well as chemical degradation during static storage can be mitigated by adding isopropanol or using deionized water. The average molecular weight of different samples of the same polymer can vary by as much as 50 percent. (Author)