非均匀布风内循环流化床中气泡特性的可视化研究

Visualized Research on Bubbling Characteristics in an Internally Circulating Fluidized Bed with Uneven Air Distribution

采用数字图像处理技术对非均匀布风内循环流化床中气泡形状、气泡尺寸沿床层高度方向的变化、气泡运动轨迹及气泡上升速度等特性进行了可视化研究。结果表明:非均匀布风内循环流化床中只在高风速区产生大量向上运动的气泡;气泡沿床层上升,气泡形状逐渐向水平方向发展,且气泡尺寸增大;气泡在上升过程中存在横向偏移,增大高风速区流化速度,气泡横向偏移量增大;沿床层高度方向,气泡运动速度有较大波动,为非均匀布风内循环流化床的设计和运行提供了科学依据和理论基础。

The bubbling characteristics in an internally circulating fluidized bed were visualizedly researched by digital image analysis,such as the shape,the movement track and the rising velocity of bubbles,as well as their size changes along bed height,etc.Results show that only in the high-velocity zone,a lot of bubbles moving upward are found to be produced in the internally circulating fluidized bed.The bubbles gradually expand along horizontal orientation and their sizes increase in the process moving upard along bed height.When the bubble moves upward,it may shift transversely,and the shift offset increases with the rise of air velocity in the high-velocity zone.The bubble’s rising velocity changes greatly along bed height.Above results may serve as a reference for the design and operation of internally circulating fluidized beds.