Anomalous effects in laminar capillary flow of polymer solutions

✍ Scribed by W. Kozicki; S.N. Pasari; A.R.K. Rao; C. Tiu

• Publisher: Elsevier Science
• Year: 1970
• Tongue: English
• Weight: 926 KB
• Volume: 25
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(70)85020-5

✦ Synopsis

The results of an investigation of the anomalous behaviour of aqueous hydroxyethyl cellulose (Natrosol-250G) solutions in the vicinity of solid surfaces, in laminar flow through capillary tubes, are presented. A resolution of the diameter effect, evidenced in the flow curves, was achieved by the evaluation of a relationship for the effective velocity at the tube wall which is a function of the wall shear stress and tube diameter and also incorporates a critical shear stress which is a function of tube diameter. The critical shear stress denotes the value of wall shear stress marking the transition from a negative effective velocity at the wall, attributable to gel formation and polymer adsorption, to a positive effective velocity of slin. ascribable to the formation of a thin layer at the wall with prop&ties approaching those of the solvent.