On-line Monitoring of Flow Process in a Spout-Fluid Bed by Combining Electrical Tomography and High-speed CCD Camera
On-line Monitoring of Flow Process in a Spout-Fluid Bed by Combining Electrical Tomography and High-speed CCD Camera
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DOI：
10.1016/j.ces.2022.118332
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发表时间：
2022-11
影响因子：
4.7
通讯作者：
Zaixing Liu;Z. Ma;Q. Tu;Shijie Sun;Lijun Xu;Ruihuan Ge;Wuqiang Yang;Haigang Wang
中科院分区：
文献类型：
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作者：
Zaixing Liu;Z. Ma;Q. Tu;Shijie Sun;Lijun Xu;Ruihuan Ge;Wuqiang Yang;Haigang Wang
为了研究矩形挡板喷动流化床内喷动流动特性，提出了一种将电容层析成像（ECT）、压力测量和高速CCD成像技术相结合的非侵入式测量方法。ECT传感器在外壁上具有12个电极，在内部具有12个电极，形成三个成像区域，每个区域中具有8个电极。喷动床中的流体动力学特性，研究了压力脉动、颗粒堆积率和喷泉形状等因素对颗粒扩散的影响。压力和颗粒填充率信号的频域分析以及ECT图像表明，喷泉形成过程中，射流区的流型由段塞流向喷动流过渡，当一侧流化速度增大时，同一区域的流型向段塞流过渡。喷动压降受侧区流化状态的影响，侧区由堵塞状态向流化状态转变时，压力信号的高特征频率降低。喷泉高度随表观气速线性增加。当气体流速较高时，由于两侧区域气压不平衡而产生的侧向气流的影响，喷泉有被抵消的趋势。
To investigate spouted flow characteristics in a rectangular spout-fluid bed with bafflers, a non-intrusive measurement approach, which combines electrical capacitance tomography (ECT), pressure measurements and high-speed CCD imaging technology, is proposed. The ECT sensor has 12 electrodes on the external wall and 12 electrodes inside, forming three imaging regions with 8 electrodes in each region. The flow hydrodynamic characteristics in the spouted bed e.g., pressure fluctuation, particle packing fraction and fountain form, are investigated. The frequency domain of pressure and particle packing fraction signals as well as ECT images indicate that the flow regime in the jet region transits from slugging to spouting in fountain formation process, and when the fluidization velocity in one side increases, the flow regime in the same region transits into slugging bed. The spouting pressure drop is affected by the fluidization condition in the side region, and the high characteristic frequency of pressure signal decreases when the side region condition changes from blockage to fluidization. The fountain height increases linearly with the superficial gas velocity. When the gas velocity is high, the fountain tends to be offset by the influence of the lateral airflow which is caused by the imbalance of the air pressure on two side regions.