DIMENSION MEASUREMENTS OF HYDRODYNAMIC ATTRACTORS IN CIRCULATING FLUIDIZED-BEDS

Experimental measurements of the correlation dimension, Kolmogorov ent ropy, and Lyapunov exponent of circulating fluidized bed (CFB) chaotic attractors were obtained by recording differential pressure and gamma -ray porosity time series along the height of a cold experimental CFB operating with 75 mu m diameter fluid catalytic cracking (FCC) catalys t. The attractor dimension did not vary with respect to the type of me asurement taken. Both differential pressure and localized gamma-ray de nsitometry measurements showed the existence of a low order hydrodynam ic attractor, whose dimension varied between 1.5 and 2.0 over the rang e of gas velocities and solids fluxes studied. Differential pressure m easurements indicated that the attractor dimension decreased slightly in the lower section of the CFB and at higher solids fluxes. Localized radial gamma-ray bed porosity measurements indicate that the attracto r dimension did not significantly vary across the bed cross-section bu t did show a tendency to be slightly lower near the riser wall.