The kinematic models of the screw-based plastifying system — a comparison in the helical coordinate system
Polimery 2000, No 3, 141
SummaryFollowing the rectangular coordinate system (cf. Polimery, 1999, 44, 600), the helical coordinate system is now used to compare two kinematic models of the screw-based plastifying system (Fig. 1). In spite of the identical formal description of some equations, the two models were found to differ essentially (Figs. 4–8) for reasons principally the same as those occurring in the Cartesian system. The highest drag (and redrag) flow and pressure flow velocities are identical in either of the coordinate systems. Therefore, differences between the models compared under maximum velocity conditions are identical in either system of coordinates. In the helical system, which allows for the real geometrical elements of the helical channel, polymer flow velocity distributions are different. Rather than linear as is the case in the Cartesian system, the drag (redrag) flow velocity distribution is not linear and the pressure flow distribution is unsymmetric.