利用光反射探测流化床中颗粒的动力学行为

采用光导纤维探测了二维流化床中运动颗粒的反射光.光探头包含三根光纤,中间一根用于发射光,上、下各一根接收粒子反射光.颗粒速度由两路反射光强度的相关分析给出.测量给出的光脉冲信号幅值和宽度随颗粒反射面积的增加而增大.三种流化数下测得的颗粒上升速度范围为0.1—0.5 m/s.床中心和过渡区测得的颗粒上升速度随流化数的增大而增大.近壁区内颗粒主要显示下降运动以及偶然的上升,尤其是在流化数较大时颗粒下降运动更明显.

Exploration of particles dynamic behavior in fluidized bed by means of light reflection

To explore the particles dynamic behavior,the reflecting optical signals from moving granules in a two-dimensional fluidized bed were sampled by using a kind of optical fiber probe.The probe consists of three parallel glass fibers: the intermediate one for transfer of emitting light,and two others for receiving reflecting signals.The granule velocities were determined by a correlation algorithm for the intensity of the reflection of light.Measurements indicated that the impulse height and width of the reflecting signals increased as reflecting area of granule went up.The granules rising velocities determined ranged from 0.1 to 0.5m/s under various fluidization numbers.In central and midway region of the bed the granule rising speed went up as the gas velocities increased.The granule movement detected in the wall vicinity showed prevailingly rising and occasionally falling,especially at high velocity of gas.