为了深入研究流化床中颗粒的流动特性和优化流化床反应器的性能,需要对流化床的运行参数如流速和电荷分布进行实时地监测.由于灵敏度高且分布均匀,网状静电传感器被用来在实验室规模鼓泡流化床上测量固体颗粒的速度廓形和电荷分布.固体颗粒的速度廓形是通过对上下游平面对应位置的静电信号进行互相关计算得到的.网状电极上的感应电荷可以通过静电信号的均方根(RMS)估算.根据电荷重建算法,利用所有电极上的感应电荷重建截面处固体颗粒的电荷分布.研究结果表明:网状静电传感器可以捕捉到鼓泡流化床床壁附近的下落颗粒;由于流化床内颗粒速度廓形的影响,传感器中心处电极上的感应电荷量大于床壁附近电极上的感应电荷量,并且重建结果显示流化床截面电荷分布相对均匀.%In order to further study the flow dynamics of particles in the fluidized bed and optimize the operating parameters of the fluidized bed reactor, real-time monitoring of the solids velocity profile and the charge distribution in the fluidized bed is needed. Due to the high and uniform sensitivity distribution, the wire-mesh electrostatic sensors were installed in a lab-scale bubbling fluidized bed to measure the velocity profile and the charge distribution of solid particles. Cross-correlation calculation of the upstream and downstream signals was applied to calculate the velocity profile of solid particles. Induced charges on the electrodes of the wire-mesh sensors were estimated by root mean square (RMS) of the electrostatic signals. Based on charge distribution reconstruction algorithm, cross sectional charge distribution was reconstructed using the induced charges from all the electrodes. The results indicate that the wire-mesh sensors can capture the falling particles near the wall. Because of the influence from the solids velocity profile, induced charge on electrode in the center of the bed is higher than that near the wall and the reconstructed charge distribution in the cross section of the bubbling bed is relatively uniform.
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