Modelling a flow of a highly viscous liquid with the boundary layer of low viscosity in an extruder

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.