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Fluidized bed technology is widely used in chemical industries. The introduction of pulsating energy into a traditional fluidized bed can effectively reduce the generation of bubbles and improve the fluidization quality. The accuracy of gas−solid distributions has a significant influence on the density control of fluidized beds. Here, a gas−solid distribution model and bed expansion prediction model were established with the wake taken as the intermediate phase to make up for the lack of a gas−solid distribution theory in a pulsed fluidized bed. The correlation coefficient of the theoretical model was validated using data obtained from collapse experiments. The linear fitting correlation between the bed expansion height H (p) and correction coefficient Y is quite good. The error of the modified model of the bed expansion ratio was found to be within 20%, which enables it to provide theoretical guidance for industrial applications of pulsed fluidized beds.

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The air dense medium fluidized bed (ADMFB), belonging to the bubbling fluidization regime, plays a critical role in dry coal beneficiation. The separation density of ADMFB depends on the understanding of bed density. Beyond the uniform hypothesis, a nonuniform hypothesis was assumed in which the bed density distribution has axial sinusoidal structures. Based on the force balance model, contact stress is responsible for the axial sinusoidal distribution. Experimentally, the fitting results of the axial sinusoidal distribution during the expansion process were presented in which the values of adj. R 2 are from 0.72 to 0.95. Through frequency domain analysis, a low frequency of 0.03 Hz defined as the global horizontal disturbance frequency is also the reason for the sinusoidal distribution. By analogy, the insect-population model could characterize the particle concentration model perfectly. Finally, the flow structure based on the above analysis was described to indicate its influence on coal separation.