Study on the flow characteristics of the pulsating intermittent liquid-solid fluidized bed with step liquid velocity by CFD approach

A new type of liquid-solid fluidized bed (LSFB), the pulsating intermittent LSFB (PI-LSFB), which uses pulsating liquid flow, was analyzed through numerical and experimental study. A good agreement between numerical simulation results and laboratory experimental measurement data was achieved. The mass transfer efficiency between the liquid and solids phases was enhanced since the relative velocity was significantly improved. The flow characteristics of the PI-LSFB were analyzed through the Eulerian-Eulerian approach, incorporating the kinetic theory of granular flow. The solids holdup in the middle part of the PI-LSFB increases first and then decreases as the step liquid velocity increases. The relative velocity increases first and then decreases as the pulsation period or the liquid velocity increases. The PI-LSFB performs similar flow regimes under step and sinusoidal liquid velocities. The proposed PI-LSFB may provide a reference in biological wastewater treatment applications.