Abstract: The flow of polypropylene (PP) in channel of screw element of a co-rotating twin screw extruder was simulated using POLYFLOW software. The three dimensional isothermal flow fields of PP in the channel of a regular and a slotted screw element were calculated. The logarithm stretching, segregation scale, and resident time of particles in the channel of regular and slotted screw elements were analyzed. The mixing performances in the two kinds of screw elements were compared through particle tracking analysis (PTA). Because of the leakage flow, the slotted screw element has lower conveying capacity, lesser dispersive mixing performance, but longer resident time and better distribution mixing performance than the regular screw element.

Key words: co-rotating twin-screw extruder, screw element, mixing performance, numerical simulation