CUED Publications database

Measurement and modelling of wall friction in the ram extrusion of stiff microcrystalline cellulose-based pastes

Ayton, HC and Rough, SL and Sutcliffe, MPF and Müller, P and Schäfer, J and Wilson, DI (2021) Measurement and modelling of wall friction in the ram extrusion of stiff microcrystalline cellulose-based pastes. Powder Technology, 377. pp. 780-794. ISSN 0032-5910

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Abstract

Simulation of paste extrusion requires knowledge of the material–wall interactions and bulk deformation behaviour. A systematic approach to decoupling these is presented for a stiff paste, comprising microcrystalline cellulose/calcium carbonate/water, employing three different experimental configurations to separate paste-wall friction from bulk rheology. The bulk yielding behaviour was identified from ram extrusion testing with orifice dies, while wall friction was characterised using the twin-die extrusion apparatus reported by Bryan et al. [1]. Further extrusion tests with square and conical entry dies featuring various die land lengths provided data for comparison with simulations. The wall friction exhibited non-linear Navier slip with negligible pressure dependency: this relationship was included within a solid mechanics-based simulation of ram extrusion with ABAQUS. The estimate of the plastic yield stress from orifice die testing was refined using simulations of flow through square-entry dies and predicted the extrusion pressure for conical-entry dies with reasonable accuracy.

Item Type: Article
Subjects: UNSPECIFIED
Divisions: Div C > Biomechanics
Depositing User: Cron Job
Date Deposited: 02 Sep 2020 20:02
Last Modified: 13 Apr 2021 10:10
DOI: 10.1016/j.powtec.2020.08.090