A qualitative study on the pulsatile flow phenomenon in a dense fly ash pneumatic conveyor--颗粒学报PARTICUOLOGY

Chen, W., Williams, K. C., Jabs, I., & Jones, M. G. (2014). A qualitative study on the pulsatile flow phenomenon in a dense fly ash pneumatic conveyor. Particuology, 17, 81–91. https://doi.org/10.1016/j.partic.2014.03.005

A qualitative study on the pulsatile flow phenomenon in a dense fly ash pneumatic conveyor

Wei Chen ^a *, Kenneth C. Williams ^a, Isabel Jabs ^b, Mark G. Jones ^a

a Centre for Bulk Solids and Particulate Technologies, Newcastle Institute for Energy and Resources, The University of Newcastle, Callaghan 2308, Australia
b Faculty of Mechanical Engineering, Leibniz University of Hanover, Hanover 30159, Germany

10.1016/j.partic.2014.03.005

Volume 17, December 2014, Pages 81-91

Received 31 October 2013, Revised 26 February 2014, Accepted 15 March 2014, Available online 19 May 2014.

E-mail: W.Chen@newcastle.edu.au; w.chentbs@gmail.com

Highlights

• Pulsatile flow patterns of gas-fly ash pneumatic flows were visualised using the ECT.

• Superficial fluidization and deaeration processes were characterised in pulsatile flows at various conditions.

• Structural and statistical analyses were performed on pulses in all flows.

Abstract

Understanding of the dynamic particulate flow structures within a dense gas-fly ash pneumatic conveyor must be improved in order to better aid its design guidance. The complex pulsatile movement of the gas-fly ash mixture dominates the flow performance within the pipeline, and historically, non-invasive measurement devices such as the electrical capacitance tomography (ECT) were often used to sufficiently capture the flow dynamics. However, inadequate studies have been conducted on the pulsatile flow phenomenon, which directly relate to the gas-fly ash two-phase flow performance. This paper aims to investigate the pulsatile flows using an ECT device. Initially, pulsatile flow patterns under various experimental conditions were obtained through ECT. Pulses within a flow were then characterised into pulse growth and decay segments, which represent the superficial fluidisation and deaeration processes during conveying. Subsequently, structural and statistical analyses were performed on the pulse growth and decay segments. Results suggested that the increasing air mass flow rate led to the decrease of the superficial fluidisation/deaeration magnitude, however, the increase of the superficial fluidisation/deaeration durations. Also, the air mass flow rate was indicated as the dominant factor in determining the pulsing statistical parameters. This research provides fundamental insights for further modelling the dense fly ash pneumatic flows.

Graphical abstract

Keywords

Pneumatic conveying; Electrical capacitance tomography; Fly ash; Pulsatile flows; Flow pattern analysis

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