(242b) Multiresolution Analysis of Pressure Fluctuations in a Gas-Solids Fluidized Bed

Gas-solids fluidized beds are widely accepted as non-linear and chaotic dynamic systems. Traditional methods such as statistical and spectral analyses are not sufficient to capture critical behavior in these systems. In this work, pressure fluctuations were used to characterize the hydrodynamics in a pseudo 2-D gas-solids bubbling fluidized bed using polyethylene powder and glass beads with comparable mean diameter. Statistical, wavelet, and chaos analyses were applied to the non-stationary signal series to extract and characterize the intrinsic features of the gas-solids fluidized bed. Dominant cycle time was calculated from approximate coefficient of scale 6 decomposed from cleaned pressure fluctuation. The global bubbling behavior of the glass bead system was greatly affected by changes in the superficial gas velocity while polyethylene powder only significantly varied with the distance from the distributor. Average cycle time, dominant cycle time and Kolmogorov entropy were also calculated from detail coefficients of scale 1-6 decomposed from cleaned pressure fluctuation to investigate flow dynamics at micro- and meso- scales. The combination of statistical, chaos and wavelet analyses proved to be an effective method to characterize multi-scale flow behavior in the gas-solids fluidized bed.