Mohsen Zarepour, Donald J. Bergstrom, Raymond J. Spiteri, 'Identifying dominant flow structures in a bubbling gas-particle fluidized bed using the spectral proper orthogonal decomposition', Chemical Engineering Science, Volume 293, 120048, 2024 https://doi.org/10.1016/j.ces.2024.120048. (https://www.sciencedirect.com/science/article/pii/S0009250924003488)
Abstract: This study applies the spectral proper orthogonal decomposition (SPOD) to analyze the spatio-temporal characteristics associated with the flow fields of a bubbling fluidized bed. The results suggest there is no singular dominant frequency linked to the highest energy levels; rather, there is a spectrum of frequencies. These frequencies are consistent with the natural frequency from published correlations. SPOD analysis allows for the capture of quasi-periodicity associated with the flow that arises from the semi-periodic evolution of bubbles in the bed and reveals the presence of multiple co-existing spatio-temporal patterns in the particle volume fraction and velocity fields. The dominant SPOD modes can be used for prediction, control, design, optimization, and reduced-order system representation. The capability of a few dominant modes to yield a low-rank reconstruction of the flow fields is demonstrated. The intermittent behavior of the bed is examined through frequency-time analysis of the gas pressure field.
Keywords: Bubbling fluidized bed; Spectral proper orthogonal decomposition; Natural frequency; Low-rank reconstruction