Investigation into Pressure Signal Fluctuations during Fluidized Dense Phase Pneumatic Conveying of Powders

Abstract

This thesis aims to provide a new method based on signal analysis for flow mode investigation in dense phase pneumatic conveying. In spite of numerous benefits offered by dense-phase pneumatic conveying of powders (which include minimum gas flows and power consumption; improved product quality and increased workplace safety etc) only limited progress has been achieved so far in understanding the fundamental transport mechanisms due to the highly concentrated and turbulent mode of the solids-gas flow. As a result, for the accurate design of dense phase pneumatic conveying systems, further research should be carried out. For carrying out analysis work, extensive amount of test data made available from University of Wollongong, Australia has been considered, which included two types of materials conveyed in different flow regimes varying from fluidized dense- to dilute phase including fly ash (median particle diameter 30 and#61549;m; particle density 2300 kg m-3; loose-poured bulk density 700 kg m-3) conveyed through a 69 mm I.D. × 168 m long pipeline and white powder (median particle diameter 55 and#61549;m; particle density 1600 kg m-3; loose-poured bulk density 620 kg m-3) conveyed through a 69 mm I.D. × 148 m long test rig. Analysis work also included data analysis from the pressure signals obtained during pneumatic conveying experiments conducted at the test setup of Thapar University, Patiala by conveying Indian fly ash (median particle diameter 19 and#61549;m; particle density 1950 kg m-3; loose-poured bulk density 950 kg m-3) through two different test set ups i.e. 54 mm I.D. × 70 m long and 54 mm I.D. × 24 m long. Various methods of analysis involve different techniques, which could be grouped into two categories.