Experimental Fluid Dynamics Study in a Fluidized Bed by Deterministic Chaos Analysis

Differential pressure fluctuations in gas-solid fluidized beds were analyzed by chaos analysis (construction of attractors, correlation dimension, Kolmogorov entropy) and mutual information. Experimental fluidization tests of three different particles were conducted. Two of them are from Geldart group B and one from Geldart group D. The fluidization experiments were performed in a cylindrical bed with 0.07 m i.d. and 1.0 m high. Pressure fluctuations were measured by three pressure transducers, and their signal time series were analyzed in the time domain (mean and standard deviation) and in the frequency domain (power spectra) for comparison and complementation of chaos analysis. Analyses in the time domain allowed a good estimation for determining whether or not the system is fluidized. The Fourier spectra provided more detailed information that could identify other phenomena such as the presence of bubbles. The chaos tools produced sensitive results, offering a qualitative and quantitative analysis for identification of the phenomena that occur in fluidization. Three different fluidization regimes could be indentified: multiple bubble bed, slugging bed, and exploding bubble bed.