Experimental Quantification of the Radial Mixing of Binary Mixtures in Annular Fluidized Beds Using the Capacitance Probe Method

Abstract

A novel measurement system for radial particle mixing in annular fluidized beds is designed on the basis of the capacitance probe method. Mixing parameters at different radial positions are acquired. The effects of the convection/diffusion mechanism on radial mixing are analyzed individually. It is found that the governing mechanism of mixing at the axial line is convection; meanwhile, diffusion is the governing mechanism of mixing near the wall. The effect of convection on radial mixing at the upper part is more important than that at the lower part. The radial dispersion coefficient ranges from 0.006 to 0.072 m2/s. At the upper part, the radial dispersion coefficient at half-radius is between 0.016 and 0.072 m2/s and that near the wall is 0.006 and 0.028 m2/s, which is four times and twice that at the same radial position and at the lower part, respectively. The radial dispersion coefficient is about 1.5 times that in two-dimensional fluidized beds.