Bed expansion in liquid-solid two-phase fluidized beds with Newtonian and non-Newtonian fluids over the wide range of Reynolds numbers

Bed expansion characteristics in Newtonian and non-Newtonian fluid-solid tw o-phase fluidized bed have been examined. Bed expansion measurements were c arried out for a bed of glass beads fluidized in Newtonian liquids (water a nd glycerol solutions) and non-Newtonian liquids (aqueous solutions of carb oxymethyl cellulose (CMC) and xanthan gum). Measurements of bed voidage cov ered a terminal particle Reynolds number from 8.14 to 3947 and a flow index in a power-law model from 1 to 0.625. The bed voidage increased with an in crease in the superficial liquid velocity and the magnitude of the increase became smaller as particle size increased. increase in viscous non-Newtoni an flow behaviour resulted in an increase of the bed voidage. The generaliz ed correlation for the bed voidage was developed for Newtonian and non-Newt onian liquid-solid two-phase systems by extending the correlation of the dr ag coefficient for single particles to multiparticle systems. The predictio ns for bed voidage were in reasonable agreement with the present experiment al data and the data in the literature for Newtonian and non-Newtonian liqu id-solid two-phase systems in the whole Reynolds number region. (C) 2001 El sevier Science B.V. All rights reserved.