Drag reducing properties of microalgal exopolymers.

Journal Article (Journal Article)

Dilute aqueous solutions of polymers released by marine phytoplankton (microalgae) were shown to effectively reduce drag in capillary pipe flow. Tests were performed in a capillary turbulent flow viscometer which extruded small samples under high pressures. In all, 22 species were screened, and the products of one chlorophyte and four rhodophyte species proved especially effective. The viscoelastic polymers produced by these species delayed the transition from laminar to turbulent flow to significantly higher Re. In general, polymeric regime segments come off the maximum drag reduction asymptote at characteristic retro-onset points, and come to lie approximately parallel to, but displaced upwards from the Prandtl-von Karman line. The delay to transition was shown to be dependent on additive polymer concentration, capillary diameter, and temperature. Ionic concentration, ionic composition, or pH had little effect on drag reducing properties.

Full Text

Duke Authors

Cited Authors

  • Ramus, J; Kenney, BE; Shaughnessy, EJ

Published Date

  • January 1989

Published In

Volume / Issue

  • 33 / 5

Start / End Page

  • 550 - 557

PubMed ID

  • 18587950

Electronic International Standard Serial Number (EISSN)

  • 1097-0290

International Standard Serial Number (ISSN)

  • 0006-3592

Digital Object Identifier (DOI)

  • 10.1002/bit.260330506


  • eng