Stokes flow through a single-screw extruder

M.G. Blyth, C. Pozrikidis

Research output: Contribution to journalArticle

4 Citations (Scopus)


Stokes flow through a single-screw extruder driven either by an axial pressure-gradient, or by the rotation of the screw, or by a combination of both is analyzed. The geometry of the screw is chosen to resemble that encountered in the metering section of a real-life industrial extruder. Working on the simplifying assumption of large helical pitch, a perturbation analysis is performed in non-orthogonal helical coordinates, and contributions to the velocity and pressure fields are computed up to second-order by finite element methods for unidirectional and two-dimensional Stokes flow. Velocity fields are presented for different screw geometries, the axial flow rate is computed for pressure- and rotation-driven flow, comparisons with simple models are made, and the effect of the pitch on the trajectories of passively convected particles is demonstrated. In the case of purely pressure-driven flow, the flow rate decreases, whereas in the case of rotating flow the flow rate increases as the gap between the screw and the barrel is reduced.
Original languageEnglish
Pages (from-to)69-77
Number of pages9
JournalAIChE Journal
Issue number1
Publication statusPublished - 2007

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