Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 11, pp. 1989
Pleiades Publishing, Ltd., 2007.
Original Russian Text ©
A.B. Golovanchikov, A.A. Shagarova, N.A. Dul’kina, I.M. Shandybina, 2007, published in Khimicheskaya Promyshlennost’,
2007, Vol. 84, No. 3, pp. 137
MODELLING AND CALCULATION
OF TECHNOLOGICAL PROCESSES
Modelling a Flow of a Highly Viscous Liquid
with the Boundary Layer of Low Viscosity in an Extruder
A. B. Golovanchikov, A. A. Shagarova, N. A. Dul’kina, and I. M. Shandybina
Volgograd State Technical University, Volgograd, Russia
Received June 1, 2007
Abstract—Features of the flow of a highly viscous liquid in an extruder with boundary layer of low viscosity
liquid at the cylinder wall and at the endless screw surface are considered. The liquid flow is modeled under
conditions of isothermal simple shift using cylindrical model of a screw canal. The profiles of rates for the stream
of a highly viscous liquid with the ring boundary layer of low-viscous liquid at the cylinder wall and at screw in
the both presence and absence of a counter pressure are calculated. Consideration of computer calculations
shows that increase in the flow rate is possible when the counter pressure tends to zero and the low-viscous liquid
forms a ring boundary layer at the cylinder wall.
Fig. 1. Scheme of moving liquid with low-viscous boundary layer near vthe wall: (a) epure of tangent tensions, (b) profile of rates (R
is ring board of two liquids, R
is a radius coreesponding to the maximal rate,
is a board where the flow rate changes sign from
plus to minus).
A physical model of such flow is shown in Fig. 1. It is
represented by a cylindrical canal with the radius R and
length l, containing inside a rod with the radius R
moving symmetrically relative the axis with angular rate
ω and rate along the axis u. The main stream of highly
moves in the ring gap R–R
, the stream
of low-viscous liquid
moves in a ring layer R
near the rod wall.
The differential equation in the tensions for axial
moving along the
axis is represented by [2, 3]:
A great amount of polymeric materials in the industry
is treated by the method of extrusion. Intensity of this
method can be increased by different ways, one is creation
of a lubricant layer between the processed material and
the canal wall.
A construction of extruder is known where the screw
wall is porous or perforated, and through the holes to it
surface is supplied a gas or low-viscous liquid .
Another variant is also possible, with the lubricant layer
near the wall of cylindrical case.
In this work we consider features of the flow of
a highly viscous liquid in an extruder with a low-viscous
boundary layer at the cylinder wall and on a screw surface.