Cross channel flow velocity and motion trajectory of polymers in a helical channel

摘要

In reference to the comparison of polymer flow along the helical channel in the screw-based plasticating system in dependence from a kinematical system,which was presented in the previous publication [1],further comparative studies on these models in the range of cross channel flow and resultant flow were conducted.Studies were carried out for both previously described models that is the model with a rotating barrel and the model with a rotating screw.It was stated that polymer cross channel flow velocity and its distribution is different in both models and in both coordinate systems (rectangular coordinate system and helical coordinate system).In a rectangular and helical coordinate system the highest values of the drag (redrag) cross channel flow velocity are the same,the differences occur in the distribution of these velocities.The distribution of the pressure flow velocity is different in both coordinate systems.The conducted analysis of the resultant flow lets us state the differences in the motion trajectory of the polymer particle in both compared models.The spiral lead of the motion trajectory of the polymer particle is higher when the barrel rotates than in the model with a rotating screw.The cause of it lies in different barrel and screw peripheral speeds.Different senses of rotation of the barrel and the screw cause laevorotatory helical motion trajectory when the barrel rotates,and dextrorotatory when the screw rotates,whereas the behaviour of the polymer particle in the vicinity of the screw flight-change of direction by pi/2 is the same.