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CFD-DEM study of effects of particle density on spout deflection behavior in a spout fluidized bed
Powder Technology ( IF 5.2 ) Pub Date : 2020-04-01 , DOI: 10.1016/j.powtec.2020.03.016
Yuanhe Yue , Tianyu Wang , Yansong Shen

Abstract Spout deflection is a typical instability phenomenon in spout fluidized beds and can greatly affect the homogeneity of the gas-solid system as well as product quality. However, few studies have been conducted to quantify the relation between the spout deflection and particle density. In this paper, the effects of particle density on the spout deflection under three scenarios are investigated, including constant fluidization velocity, scaled-up fluidization velocity and time-dependent particle density. The spout deflection angle is used to quantify spout deflecting movement. The results show that non-alternating spout deflection happens if particle density is less than 2130 kg/m3 at a constant fluidization velocity. The amplitude, deflection speed and regularity of alternating spout deflection keep unchanged if particle density ranges from 2230 kg/m3 to 3830 kg/m3 at a constant fluidization velocity. Then, when particle density ranges from 1830 kg/m3 to 3830 kg/m3 and meanwhile fluidization velocity are scaled up, alternating spout deflection also happens, where the main characteristics of alternating spout deflection, including amplitude, deflection speed and regularity, however, keep constant even if particle density varies. In addition, if particle density is changed with time, the amplitude, deflection speed and regularity of the alternating spout deflection will also keep constant, indicating that the hydrodynamics of the alternating spout deflection has little relationship with initial particle position state and particle density. This study confirms the effects of particle density on the spout deflection behavior in the spout fluidized bed.

中文翻译:

CFD-DEM 研究颗粒密度对喷口流化床喷口偏转行为的影响

摘要 喷口偏转是喷口流化床中一种典型的不稳定现象,对气固体系的均一性和产品质量有很大影响。然而,很少有研究对喷口偏转和颗粒密度之间的关系进行量化。在本文中,研究了三种情况下颗粒密度对喷口偏转的影响,包括恒定流化速度、放大流化速度和随时间变化的颗粒密度。喷口偏转角用于量化喷口偏转运动。结果表明,在恒定流化速度下,如果颗粒密度小于 2130 kg/m3,则会发生非交替喷口偏转。幅度,在恒定流化速度下,颗粒密度在2230 kg/m3至3830 kg/m3范围内时,交替喷口偏转的偏转速度和规律保持不变。然后,当颗粒密度在 1830 kg/m3 到 3830 kg/m3 范围内,同时流化速度按比例增加时,也会发生交替喷口偏转,其中交替喷口偏转的主要特征包括幅度、偏转速度和规律性,但保持即使粒子密度变化,也保持不变。此外,如果粒子密度随时间变化,交替喷口偏转的幅度、偏转速度和规律也将保持不变,说明交替喷口偏转的流体动力学与初始粒子位置状态和粒子密度关系不大。
更新日期:2020-04-01
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