Al-Ghurabi Ebrahim H, Shahabuddin Mohammed, Kumar Nadavala Siva, Asif Mohammad
Department of Chemical Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia.
Department of Physics and Astronomy, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia.
Nanomaterials (Basel). 2020 Feb 23;10(2):388. doi: 10.3390/nano10020388.
Low-frequency flow pulsations were utilized to improve the hydrodynamics of the fluidized bed of hydrophilic ultrafine nanosilica powder with strong agglomeration behavior. A gradual fluidization of unassisted fluidized bed through stepwise velocity change was carried out over a wide range of velocities followed by a gradual defluidization process. Bed dynamics in different regions of the fluidized bed were carefully monitored using fast and sensitive pressure transducers. Next, 0.05-Hz square-wave flow pulsation was introduced, and the fluidization behavior of the pulsed fluidized bed was rigorously characterized to delineate its effect on the bed hydrodynamics by comparing it with one of the unassisted fluidized bed. Flow pulsations caused a substantial decrease in minimum fluidization velocity and effective agglomerate diameter. The frequencies and amplitudes of various events in different fluidized bed regions were determined by performing frequency domain analysis on real-time bed transient data. The pulsations and their effects promoted deagglomeration and improved homogeneity of the pulsed fluidized bed.
利用低频流动脉动来改善具有强烈团聚行为的亲水性超细纳米二氧化硅粉末流化床的流体动力学。通过逐步改变速度，在很宽的速度范围内对无辅助流化床进行逐步流化，随后进行逐步脱流态化过程。使用快速且灵敏的压力传感器仔细监测流化床不同区域的床层动力学。接下来，引入0.05赫兹的方波流动脉动，并通过与无辅助流化床之一进行比较，严格表征脉冲流化床的流化行为，以描述其对床层流体动力学的影响。流动脉动导致最小流化速度和有效团聚体直径大幅降低。通过对实时床层瞬态数据进行频域分析，确定了不同流化床区域各种事件的频率和幅度。脉动及其影响促进了团聚体的解聚，并改善了脉冲流化床的均匀性。
