Accession Number:

ADA217492

Title:

Investigation into the Mechanism of Polymer Thread Drag Reduction

Descriptive Note:

Technical rept. 1 Dec 1988-30 Nov 1989

Corporate Author:

PURDUE UNIV LAFAYETTE IN SCHOOL OF MECHANICAL ENGINEERING

Report Date:

1990-01-01

Pagination or Media Count:

72.0

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.

Subject Categories:

  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE