The flow of dilute aqueous solutions of macromolecules in various geometries. III. Bent pipes and porous materials

Abstract

For pt.II see ibid., vol.9, no.5, p.735 (1976). The fluids used were deionized boiled water, aqueous solutions of polyacrylamide P250 (100 ppm, 5 ppm) and of 'Kelzan' (10 ppm). The temperature of the experiments was 20.0+or-0.2 degrees C. A theoretical master curve was produced from Dean (1972) and from McConalogue and Srivastava (1968) for flow through bent pipes. Because of the straight parts in our test sections there were small departures between experimental results for water and those predicted by the master curve. Because of curvature, departures were marked for the polymer solutions, as though measurable Dean flow was delayed to higher values L' of Dean Number L. (Ls'-Lw')/Ls' was denoted by Delta L where s referred to solution and w to water then Delta L increased with rate of shear at Ls'. For a bed of glass beads as for bent pipes, measurable inertial effects in the flow were delayed to higher values of L. For porous discs 'polymer effects' occurred at slow flows where inertial effects did not occur.