An Investigation of the Pipe Flow of Dilute Polymer Solutions
Basic reseaches for the application of the Toms' effect to hydraulic transportation of solids (1st Report)
1974 Volume 90 Issue 1041 Pages 705-710
Details
1974 Volume 90 Issue 1041 Pages 705-710
The phenomenon of frictional drag reduction with dilute polymer solutions in turbulent flow is well known as the Toms'effect.
Carrier fluid and polymer additives used in this test are fresh water, artificial sea water, polyethyleneoxide (PEO, 18N) and polyacrylamide (SEPARAN, AP30).
The relationship between the drag-reducing effect of solutions and the amount of the polymer additives in the carrier fluid is semi-theoretically analyzed, and in case of pumping the solution with a volute pump the mechanical degradation of solution is tested.
The experimental results are as follows.
(1) Pressure drop in turbulent pipe flow of fresh water can be reduced by about 78% when a small amount (20-100ppm) of PEO or SEPARAN is dissolved in the water.
(2) The correlations on the maximum drag reduction in turbulent pipe flow of dilute polymer solutions are formulized as follows:
1/√λ=8.5logRe√λ-16.6 (PEO-fresh water system) 1/√λ= 12.4 logRepλ1-n/2-22.1 (SEPARAN-fresh water system) whereλ=resistance coefficient of pipe flow, Re=usual Reynolds number, Rep=generalized Reynolds number and n = flow behavior index.
(3) Each of all solutions of PEO-fresh water, of PEO-artificial sea water, and of SEPARAN-fresh water show high drag reduction. The SEPARAN is less stable in artificial sea water and shows only a little drag reduction, but stabler than PEO in fresh water against mechanical degradation.
