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Power consumption of partially filled twin‐screw extruders
Author(s) -
Secor R. M.
Publication year - 1986
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.760261402
Subject(s) - materials science , rotational speed , mechanics , viscosity , power (physics) , plastics extrusion , mixing (physics) , torque , dissipation , shear thinning , mechanical engineering , composite material , thermodynamics , engineering , physics , quantum mechanics
Abstract Twin‐screw extruders are used very effectively, when partially filled, for mixing and surface renewal of high‐viscosity fluids. The rate of energy input, often sufficiently high to be a major design consideration, determines the drive power, the heat input to the fluid, and the cooling requirements. Operating limitations may be fixed by thermal degradation of the material being processed. A simple model for the rate of energy dissipation in twin‐screw extruders predicts that the power input is proportional to the square of the screw speed. Measurements were made of shaft torque and screw speed for polyisobutylene passing through a large twin‐screw extruder having co‐rotating shafts. The experimental procedure avoids the problems of changes in holdup and temperature that accompany changes in screw speed under steady state conditions. The power input was found to be proportional to the screw speed raised to the exponent 1.90. This result was attributed to slightly pseudoplastic behavior of the fluid in the radial clearances.