Investigation into the Mechanism of Polymer Thread Drag Reduction

Abstract

This study investigated the mechanism of drag reduction that occurs when a long chain, high molecular weight polymer is injected along the centerline of a pipe with a concentration high enough to form a coherent unbroken thread. The objective of this study was to test the hypothesis that drag reduction is caused by the diffusion of polymer molecules from the thread into the near-wall region of the pipe. The objective was realized through the measurement of the polymer concentration in the near-wall region, the drag reduction and the radial location of the thread. The concentration was measured using a laser induced fluorescence technique where the polymer was marked with fluorescein dye. The experiments were conducted in a 3.18 cm diameter, clear acrylic pipe at Re = 40,000 using a 5000 ppm concentration solution of Separan AP 273 as the injectant. The drag reduction increased from zero at the point of injection to a maximum value about 200 diameters downstream of the injector.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1990
Accession Number
ADA217492

Entities

People

  • Ronald E. Smith
  • William G. Tiederman

Organizations

  • Purdue University

Tags

Communities of Interest

  • Ground and Sea Platforms
  • Space

DTIC Thesaurus Topics

  • Acquisition
  • Boundary Layer
  • Channel Flow
  • Coefficients
  • Data Acquisition
  • Flow Visualization
  • Fluid Flow
  • Laser Induced Fluorescence
  • Measurement
  • Mechanical Engineering
  • Pipe Flow
  • Reynolds Number
  • Strain Rate
  • Turbulent Flow
  • Turbulent Mixing
  • Video Recording
  • Water Flow

Readers

  • Combustion and Flow Dynamics.
  • Fluid Mechanics and Fluid Dynamics.
  • Materials Science and Engineering.

Technology Areas

  • Directed Energy
  • Directed Energy - Lasers