ISSN 1070-4272, Russian Journal of Applied Chemistry, 2015, Vol. 88, No. 1, pp. 118−123. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © V.N. Manzhai, Yu.R. Nosikova, A.V. Abdusalyamov, 2015, published in Zhurnal Prikladnoi Khimii, 2015, Vol. 88, No. 1, pp. 124−130.
Degradation of Polymer Solutions in a Turbulent Flow
in a Cylindrical Channel
V. N. Manzhai
, Yu. R. Nosikova
, and A. V. Abdusalyamov
Institute of Petroleum Chemistry, Siberian Branch, Russian Academy of Sciences,
Akademicheskii pr. 3, Tomsk, 634021 Russia
National Research Tomsk Polytechnic University, pr. Lenina 30, Tomsk, 634050 Russia
National Research Tomsk State University, pr. Lenina 36, Tomsk, 634050 Russia
Received December 24, 2014
Abstract—Water- and oil-soluble polymers capable to reduce the turbulent ﬂ ow drag were studied. The cause
of a decrease in the Toms effect under various conditions was determined. Recommendations were formulated
for optimum use of the polymers in pipeline transport technologies.
The phenomenon of drag reduction (Toms effect) has
found wide use in power-saving technologies for pipeline
transport of liquids [1–6]. However, already early studies
of the drag reduction effect revealed instability of polymer
solutions in a shear rate ﬁ eld [7, 8]. This instability is
often attributed to the degradation of macromolecules.
The degradation leading to cleavage of covalent bonds in
the polymer backbone and to a decrease in the molecular
mass can be caused by different factors: heating of the
solution or mechanical action in the course of its stirring,
passing through sites of local resistance in pipeline
networks or through pipe segments with longitudinal
extension , action of oxidants, etc. It is also noted
 that the capability of a polymer solution for drag
reduction gradually decreases with the distance of ﬂ ow
in the pipe or with an increase in the number of passages
through a cylindrical channel in an open installation.
The degradation intensity increases with an increase
in the shear stress on the pipe wall, and upon passage
through pump stations of long-distance main pipelines
the performance of antiturbulent additives decreases
virtually to zero . Today, there is also another, less
widespread viewpoint concerning instability of polymer
solutions. Makogon et al.  attributed the observed
decrease in the effect not to a decrease in the molecular
mass of the polymer due to polymer chain break but to
degradation of polymer solutions, without explaining the
physicochemical sense of this term.
The problem of mechanical degradation of macromol-
ecules in a turbulent ﬂ ow of polymer solutions seriously
complicates efﬁ cient use of antiturbulent additives in
pumping of liquids along main pipelines. Such pipelines
are operated, as a rule, at very high Reynolds numbers
(Re ~ 1 × 10
–1 × 10
) and relatively low shear stresses
on pipe walls (τ
~ 1–10 Pa).
This study was aimed at revealing the cause of the
decrease in the Toms effect under various conditions
and at formulating recommendations for optimum use of
polymers in pipeline transport technologies.
As investigation objects we used both water- and
oil-soluble polymer samples. Hydrodynamic tests of
the solvents and polymer solutions were performed
on a turbulent rheometer, which was simple in design
and similar to a capillary viscometer, but allowed
hydrodynamic studies to be performed under the
conditions of both laminar and turbulent liquid ﬂ ow.
The turborheometer, which is an open-type installation,
is described in [3, 11, 12]. As found in experiments ,
on introducing a high-molecular-mass polymer into