三维电容层析成像传感器优化及循环流化床提升管轴向流动成像  

Optimization of three-dimensional ECT sensor and imaging of CFB riser in the axial direction

作　　者：吴章友 杨道业 卞启涛 张晨晓 WU Zhangyou;YANG Daoye;BIAN Qitao;ZHANG Chenxiao(College of Electrical Engineering and Control Science,Nanjing Tech University,Nanjing 211816,Jiangsu,China)

机构地区：[1]南京工业大学电气工程与控制科学学院,江苏南京211816

出　　处：《化工进展》2021年第12期6532-6539,共8页Chemical Industry and Engineering Progress

基　　金：国家自然科学基金(51106070)。

摘　　要：由于多相流流动的复杂性和不透明性,对气固两相流循环流化床提升管轴向行为研究一直是亟待解决的难题。本文采用八截面三十二电极的三维电容层析成像(ECT)传感器,每个截面包含4个电极,分析了在不同轴径比(轴向长度与传感器内径之比)和不同电极覆盖率下的成像情况。仿真结果表明,当轴径比为8.3、电极覆盖率达到69%时,在保证成像质量的情况下达到最大的轴径比。开发了一套32通道的三维ECT数据采集系统用于流化床提升管流动成像,成像速度为每秒120帧。成像结果表明,当流化气速Uf为2.34m/s时,段塞流在加速上升到一定高度后,由于气速和颗粒速度差降低带来的曳力减小而破裂。本系统可以有效揭示循环流化床(CFB)的三维动态特征。Because of the complexity and opacity of multi-phase flow,it has always been a difficult problem to study the axial behavior of the riser of the gas-solid circulation fluidized bed.In this paper,a 32-electrode three-dimensional electrical capacitance tomography(ECT)sensor with eight planes was used,each of which contained four electrodes.The imaging was analyzed at different aspect ratios(the ratio of axial length to sensor inner diameter)and different electrode coverage.The simulation results showed that the maximum aspect ratio was achieved under the condition of ensuring imaging quality when the aspect ratio was 8.3 and the electrode coverage reached 69%.A 32-channel 3D ECT data acquisition system with an imaging speed of 120 frames per second was developed to reveal the flow detail in the axial direction.The imaging results showed that when the superficial gas velocity Uf is 2.34m/s,the slug flow broke due to the decrease of drag force caused by the decrease of the difference between the gas velocity and the particle velocity.The experiment indicated that the ECVT system could reveal the dynamic characteristics of the three-dimension circulating fluidized bed(CFB).

关 键 词：三维电容层析成像 轴径比 轴向流动 循环流化床 

分 类 号：TB934[一般工业技术—计量学]