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Flow field analysis of the kneading disc region in a co‐rotating twin screw extruder
Author(s) -
Yang HaurHorng,
ManasZloczower Ica
Publication year - 1992
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760321903
Subject(s) - mixing (physics) , plastics extrusion , materials science , flow (mathematics) , mechanics , mechanical engineering , pressure gradient , compounding , engineering drawing , composite material , engineering , physics , quantum mechanics
Abstract Co‐rotating, intermeshing twin screw extruders are widely used in polymer compounding and blending. Among the different modules of the co‐rotating twin screw extruder, the kneading discs are the dominant ones in determining mixing efficiency. The major difficulty in solving the flow problem in the kneading disc region arises from the complex geometry and the time‐dependent flow boundaries as the discs rotate. In this work, a fluid dynamics analysis package—FIDAP—using the finite element method was employed to simulate the flow patterns in the kneading disc region of a Werner & Pfleiderer ZSK‐30 co‐rotating twin screw extruder. The problem of time dependent flow boundaries was solved by selecting a number of sequential geometries to represent a complete mixing cycle. The flow field was characterized in terms of velocity profiles, pressure distributions, shear stresses generated and a parameter λ quantifying the elongational flow components. The last two parameters are the most important ones in analyzing mixing efficiency. The influence of design variables (stagger angle, right or left handed configuration) and processing conditions (rpm, axial pressure gradient) on the flow characteristics was analyzed.