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MODELING the AVERAGE SHEAR RATE IN A CO‐ROTATING TWIN SCREW EXTRUDER
Author(s) -
MOHAMED IBRAHIM O.,
OFOLI ROBERT Y.,
MORGAN RON G.
Publication year - 1990
Publication title -
journal of food process engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 45
eISSN - 1745-4530
pISSN - 0145-8876
DOI - 10.1111/j.1745-4530.1990.tb00052.x
Subject(s) - plastics extrusion , shear rate , shearing (physics) , materials science , shear (geology) , mechanics , mechanical engineering , work (physics) , heat transfer , composite material , rheology , engineering , physics
A procedure similar to the one commonly used with mixers has been utilized to develop a model for estimating the shear rate in co‐rotating twin screw extruders. Newtonian and non‐Newtonian fluids were used to estimate the average shear rate for three screw configurations of a Baker Perkins (MPF‐50D) twin screw extruder. As would be expected, the shear rate was highly correlated to the screw speed. At a given screw speed, 30 forwarding paddles generate the highest rate of shear, followed by feed screws and single lead screws. No data was found in the published literature to provide comparison with the results of this work. However, the model has performed well in heat transfer analysis of twin screw processes. The procedure is sensitive to screw configuration, accounts for the shearing effects in the different regions within the extruder barrel, and covers a range of screw speeds (100–400 RPM) typical of what is encountered in industrial pilot plants. Even though much more work remains to be done before the shear rate can be confidently characterized for composite screw configurations, this technique provides a sound foundation.