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.

中文翻译：

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使用振动缓解喷口床的不稳定性：实验和 CFD-DEM


众所周知，喷口床的不稳定性，如喷口偏转和喷口摆动，会降低颗粒再循环速率，从而降低干燥和混合效率。最近的一项研究 （Punch et al.， Chem. Eng. J.， 2024 495， 153459） 表明，垂直振动可用于减少大颗粒在低床高下干湿喷床的喷口不稳定性，而不会影响再循环速率。在这里，我们通过实验表明，垂直振动也可用于减少具有大入口直径与粒径比 （>20） 的干燥颗粒喷口床的喷口不稳定性，这些颗粒传统上非常不稳定，并提出了一个状态图来指导工业振动喷口床的放大。数值 CFD-DEM 模拟用于阐明垂直振动喷口床的机制，并揭示垂直振动在每个振动周期中产生一个力波，该力波垂直传播穿过喷口，并使颗粒再循环速率均匀地进入喷口，减轻喷口的不稳定性。