Dependence of Drag Reduction on Polymer Size Distribution and Configuration
The suppression of turbulence in fluids due to the addition of high molecular weight polymers has been the subject of much study (1). Recently, we postulated (2) that polymers function as drag reducing agents on a molecular level by inhibiting the coalescence of microvortexes present in the solvent, thereby delaying the onset of bulk turbulence. These arguments rationalize the known dependence of drag reduction effectiveness (DRE) on such variables as solute concentration, molecular weight and chain flexibility. Further, the concept indicates that in a polymer with broad molecular weight distribution, it should be the high molecular weight end of the distribution which dominates the DRE performance, much as the bulk viscosity is dominated by these long chains. One of the purposes of this communication is to test the concept experimentally.
KeywordsDrag Reduction Chain Conformation High Molecular Weight Polymer Solvent Quality Polymer Conformation
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- (1).For example: A. White, Drag Reduction by Additives, Review and Bibliography, BfiRA fluid engineering, Cranfield, England (1976).Google Scholar
- (5).A. Charlesby, “Aspects of Radiation Reactions in Polymers” in Energetics and Mechanisms in Radiation Biology, G.O. Phillips, Ed. Academic Press, N.Y. (1968).Google Scholar
- (6).E. Kiran and F. Rodriguez, XXIII Int. Congress of Pure and Appl. Chem. 8, 175 (1971).Google Scholar