Numerical simulation of flow and distributive mixing in pin-barrel extruder

Based on the reasonably simplified model of single-screw extrusion process,the influence of the number and row distance of pins,the width of helical groove and the dragging velocity on the flow and distributive mixing around the unfolded surface of screw in pin-barrel extruder was investigated by the sliding mesh technology and taking the movement between pins and screw into account.The results showed that the cuts in the pins and flights intensified the distributive mixing significantly;and the mixing efficiency could be improved by reducing the row distance of pins and the width of helical groove,and increasing the pin number and dragging velocity.For Φ90 pin-barrel extruder,the better distributive mixing could be obtained by using 6~8 pins in a row,60~72 mm row distance of pins,54 mm width of groove and 25~50 r·min (-1) screw speed.