基于数字图像技术的垂直流化床气泡分析

The Bubble Analysis of Vertical Fluidized-Bed Based on Digital Image Technology

通过高速摄影系统获得流化床内气固两相流图像,采用数字图像技术进行处理,进而得到垂直流化床中气泡上升过程中形状特性、运动轨迹和气泡面积变化规律,以及气泡聚合过程中形心位置和面积的变化规律。实验结果表明:气泡在上升过程中颗粒越小,空气压差越大,气泡越易呈现球帽状;气泡上升时呈现一定的螺旋上升特性,且空气压差越小,颗粒越大,螺旋性越明显;气泡聚合过程实际上是由于小气泡受大气泡吸引而成。

Gas-solid two-phase flow images in vertical fluidized-bed were obtained by High-speed photography system,and processed by digital image technology.Then the thesis about bubble shape variation characteristics,trajectory and bubble size variation when bubble rose in the vertical fluidized bed,and the bubble-centroid position and bubble-size variation when the bubble aggregate in the vertical fluidized-bed were acquired.The results show that the smaller the particles,the greater the air differential pressure,the more easily bubble presents cap-shaped when the bubble rises in the vertical fluidized-bed.The bubble spiral in the vertical fluidized-bed,and the smaller air differential pressure,the bigger particles,the more obvious the spiral.The bubble aggregation process is actually due to the large bubbles formed by attracting small bubbles.