Mitigation of Spouted Bed Instabilities Using Vibration: Experiments and CFD-DEM

Spouted bed instabilities, such as spout deflection and spout oscillation, are well understood to decrease the particle recirculation rate, which decreases drying and mixing efficiency. A recent study (Punch et al., Chem. Eng. J., 2024 495, 153459) showed that vertical vibration could be used to decrease spout instabilities in dry and wet spouted beds at low bed height for large particles, without compromising recirculation rate. Here, we show experimentally that vertical vibration can also be used to reduce spout instabilities for spouted beds of dry particles with a large inlet diameter to particle diameter ratio (>20), which are traditionally highly unstable, and present a regime map to guide scale-up of industrial vibrated spouted beds. Numerical CFD-DEM simulations are used to elucidate the mechanisms of vertically vibrated spouted beds and reveal that vertical vibration produces a force wave each vibration cycle which propagates vertically through the bed and homogenizes the particle recirculation rate into the spout, mitigating spout instabilities.