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Experimental and Computational Multiphase Flow

Article Title

Pressure fluctuation instability in vertical plug formation of coarse particles with a non-mechanical feeder

Keywords

flow instability, pressure fluctuations, plug flow, dense-phase pneumatic conveying, granular materials, high-temperature gas-cooled reactor

Abstract

Plug conveying receives attention due to its advantages such as low particle attrition, low pipeline wear, and low energy consumption. Based on the background of pneumatic transportation of absorber spheres in the small absorber sphere system of pebble bed HTGR, a novel non-mechanical feeder for plug formation of coarse particles has been proposed in our previous work. We further investigate the pressure fluctuation instability in the vertical plug formation of coarse particles with the non-mechanical feeder. Experiments for plug formation are conducted with glass beads of three kinds of particle diameter (dp = 6, 4, and 2 mm). The results show that micro-scale instabilities along with macro-scale instabilities are observed for the pressure fluctuations of feeder gas inlet in the vertical plug formation for the three particle diameters. It is interesting to find that the micro-scale instabilities decrease first and then increase with superficial gas velocity increasing for dp = 6 and 4 mm glass beads, respectively. The present study provides a further understanding of the pressure fluctuation instabilities in vertical plug formation of coarse particles with the non-mechanical feeder, which can contribute for on-line monitoring and operation optimization of dense-phase gas–solid flows with coarse particles.

Publisher

Tsinghua University Press

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