An investigation into flow mode transition and pressure fluctuations for fluidized dense-phase pneumatic conveying of fine powders--颗粒学报PARTICUOLOGY

Mittal, A., Mallick, S. S., & Wypych, P. W. (2014). An investigation into flow mode transition and pressure fluctuations for fluidized dense-phase pneumatic conveying of fine powders. Particuology, 16, 187–195. https://doi.org/10.1016/j.partic.2014.03.006

An investigation into flow mode transition and pressure fluctuations for fluidized dense-phase pneumatic conveying of fine powders

A. Mittal ^a *, S.S. Mallick ^a, P.W. Wypych ^b

a Department of Mechanical Engineering, Thapar University, Patiala, Punjab 147004, India
b Faculty of Engineering and Information Sciences, University of Wollongong, Wollongong, NSW 2500, Australia

10.1016/j.partic.2014.03.006

Volume 16, October 2014, Pages 187-195

Received 7 September 2013, Revised 28 January 2014, Accepted 4 March 2014, Available online 27 May 2014.

E-mail: anumittal_m@yahoo.co.in

Highlights

• Straight pipe PCC showed gradual variation of pressure with mass flow rate of air.

• Pressure fluctuations were investigated using standard deviation and Shannon entropy.

• Shannon entropy and standard deviation values tended to decrease after flow through bend(s).

• Shannon entropy variation along the pipeline length provided insight into change in flow.

• Flow turbulence increases along the length of pipeline.

Abstract

This paper presents the results of an ongoing investigation into the fluctuations of pressure signals due to solids–gas flows for dense-phase pneumatic conveying of fine powders. Pressure signals were obtained from pressure transducers installed along different locations of a pipeline for the fluidized dense-phase pneumatic conveying of fly ash (median particle diameter 30 μm; particle density 2300 kg/m³; loose-poured bulk density 700 kg/m³) and white powder (median particle diameter 55 μm; particle density 1600 kg/m³; loose-poured bulk density 620 kg/m³) from dilute to fluidized dense-phase. Standard deviation and Shannon entropy were employed to investigate the pressure signal fluctuations. It was found that there is an increase in the values of Shannon entropy and standard deviation for both of the products along the flow direction through the straight pipe sections. However, both the Shannon entropy and standard deviation values tend to decrease after the flow through bend(s). This result could be attributed to the deceleration of particles while flowing through the bends, resulting in dampened particle fluctuation and turbulence. Lower values of Shannon entropy in the early parts of the pipeline could be due to the non-suspension nature of flow (dense-phase), i.e., there is a higher probability that the particles are concentrated toward the bottom of pipe, compared with dilute-phase or suspension flow (high velocity), where the particles could be expected to be distributed homogenously throughout the pipe bore (as the flow is in suspension). Changes in straight-pipe pneumatic conveying characteristics along the flow direction also indicate a change in the flow regime along the flow.

Graphical abstract

Keywords

Fluidized dense-phase; Pneumatic conveying; Fine powders; Shannon entropy; Flow transition; Particle turbulence

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