An experimental investigation of turbulent flow drag reduction was conducted using dilute solutions of poly(ethylene oxide) flowing in capillary tubes. Flow through capillary tubes was chosen as a means to (1) obtain a large ratio of solid surface area to fluid volume, and (2) obtain high shear stresses at low Reynolds numbers. This allowed investigation of surface effects and polymer degradation as a function of a number of variables which are known to influence drag reduction. The experimental evidence shows an increase in the maximum Reynolds number at the onset of degradation with increasing surface free energy of the tube coatings. Consequently, drag reduction increases with increasing surface free energy, at equal Reynolds numbers, at the onset of degradation. A semiflexible film hypothesis is presented. Emphasis is placed on the importance of surface viscosity and Gibbs elasticity of an adsorbed or hydrogen bond associated polymer film and not on turbulence suppression by individual polymer molecules. A wall associated polymer film, exhibiting optimum surface rheology characteristics, may act to inhibit turbulence generation in the wall region and thus stabilize flow and rated the onset of degradation.

  • Corporate Authors:

    American Institute of Chemical Engineers

    345 East 47th Street
    New York, NY  United States  10017
  • Authors:
    • Felsen, I M
    • Smith, T G
  • Publication Date: 1973

Media Info

  • Features: References;
  • Pagination: p. 58-68
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00050523
  • Record Type: Publication
  • Source Agency: Engineering Index
  • Files: TRIS
  • Created Date: Jan 11 1974 12:00AM