Estimation of Particle Dispersion Characteristics in a Fluidized Bed with the Binary Mixture of Geldart A and B Types Using the Optical Fiber Probe Method

This study proposes a novel method for experimentally assessing particle dispersion characteristics within a binary-mixture fluidized bed. Verification experiments were conducted, demonstrating satisfactory agreement between the measured results obtained from the optical fiber probe and actual values. Using this method, investigations were carried out to elucidate the flow mechanisms and the influence of key operational parameters on the radial, axial, and overall particle dispersion characteristics. The findings reveal that particle dispersion within the binary-mixture fluidized bed is influenced by the viscous stresses between particles and the initial packing state. Specifically, Geldart-A particles act as the flotsam phase, while Geldart-B particles serve as the jetsam phase. When the initial packing ratio of the flotsam phase exceeds 70%, viscous stresses between particles primarily govern the dispersion characteristics. Increasing the superficial gas velocity weakens the viscosity effect, enhancing radial and axial dispersion uniformity. Conversely, when the initial packing ratio of the jetsam phase surpasses 70%, the dispersion characteristics are predominantly influenced by the saturation degree of the particle packing. Higher gas velocity exerts a greater impact on radial dispersion as well as axial and overall dispersion characteristics. Generally, a higher flotsam phase packing ratio or superficial gas velocity promotes a more uniform particle dispersion within the bed. The proposed optical fiber probe method proves to be effective in measuring particle dispersion in binary-mixture systems, contributing to advancements in measurement theories and techniques for industrial binary-mixture fluidization.

Duke Scholars

Author Andrew Bragg Civil and Environmental Engineering