Effect of orientation on the drag of a cone settling in a Bingham plastic fluid--颗粒学报PARTICUOLOGY

Mishra, P., Tiwari, A. K., & Chhabra, R. P. (2019). Effect of orientation on the drag of a cone settling in a Bingham plastic fluid. Particuology, 43, 157-170. https://doi.org/10.1016/j.partic.2018.02.004

Effect of orientation on the drag of a cone settling in a Bingham plastic fluid

Pragya Mishra ^a, A.K. Tiwari ^{a b}, R.P. Chhabra ^a *

a Department of Chemical Engineering, Indian Institute of Technology, Kanpur 208016, India
b M2NeT Laboratory, Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON N2L 3C5, Canada

10.1016/j.partic.2018.02.004

Volume 43, April 2019, Pages 157-170

Received 17 May 2017, Revised 25 January 2018, Accepted 22 February 2018, Available online 1 September 2018, Version of Record 19 February 2019.

E-mail: chhabra@iitk.ac.in

Highlights

• Cone angle had moderate effect on the total drag coefficient.

• Fluid yield stress tended to stabilize the flow field.

• The drag coefficient exhibited a positive dependence on Bingham number.

• The drag coefficient was only weakly dependent on the cone orientation.

Abstract

Effects of the orientation and apex angle on the settling velocity of conical particles in Bingham plastic fluids are numerically investigated over a Reynolds number range of 1 ≤ Re ≤ 100, Bingham number range of 0 ≤ Bn ≤ 100, and cone angle range of 20° ≤ α ≤ 150°. Governing equations (of continuity and momentum) are solved numerically using the finite element method to obtain velocity and pressure fields that are postprocessed to obtain values of the drag coefficient. Furthermore, the effect of cone orientation on the flow field is visualized and explored in terms of streamline contours and the morphology of yielded/unyielded regions. Finally, the obtained values of drag are correlated via a simple predictive expression in terms of the modified Reynolds number. The effect of the cone angle on drag is found to be moderate because the drag force acting on the lateral surface is a small fraction of the overall drag.

Graphical abstract

Keywords

Bingham number; Reynolds number; Yielded/unyielded regions; Drag

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