An improved method to process the data of optical Fiber signals for identifying the instantaneous flow structure in a gas-solid fluidized bed

The instantaneous signals recorded with the optical fiber probe (OFP) directly reflect the hydrodynamic behaviors in fluidized beds. A new data-processing method is put forward to calculate the threshold voltage that is used to discern the bubble phase and emulsion phase. It is found that the threshold voltage is not only related to the flow pattern but also to the color of the used particles. Then the data-processing programs including the Fast Fourier filter have been developed for determining the flow characteristics such as the bubble/particle velocity, bubble/agglomerations chord length, etc. By comparing them with other different methods, the suitability of the proposed method for quantifying the hydrodynamic behaviors in bubble/turbulent fluidized beds is verified. Finally, this method is employed to analyze the characteristics of bubbles, agglomerations and particles in a gassolid fluidized bed. It is found that the hydrodynamic behaviors of bubbling beds and turbulent beds have significant differences.