Effective drag coefficient correlation for coarse coal particle fluidization in transitional flow regime

Abstract

Liquid–solid fluidized beds are widely used in industrial processes, such as polymerization, mineral processing, and water treatment. Among these processes, particle fluidization behaviors perform a significant function in determining heat and mass transfer performance. In this study, a large set of expansion experiments are performed to investigate the effects of the particle density, particle size, and liquid superficial velocity on bed expansion height and bed porosity. The drag coefficient is obtained based on experimental data. The relationship between drag coefficient and Reynolds number, Froude number and Stokes number is clarified, and an effective drag closure for coarse coal particle fluidization in the transitional flow regime is proposed. Then the developed drag coefficient correlation is incorporated into liquid–solid two-phase flow model to predict the bed expansion height. The output predictions agree well with the experimental data, ensuring the accuracy of the proposed drag closure.