循环流化床中气固两相流动特性的可视化研究

在自行设计并搭建的试验台上，利用CCD的图像快速采集功能，获得了不同气速下流化床内的流态图像，并用图像处理方法对这些原始图像进行了有效的处理。研究了贴壁回探流、气体局部扩散系数、局部空隙率随横向位置和高度的分布、气泡的上升速度，给出了实验中气泡边界曲线的分维数。实现了循环流化床内气固两相流体动力学特性的可视化，为图像处理技术应用到循环流化床作了有益的尝试。

A Visual Study of the Gas-solid Dual-phase Flow Characteristics in a Circulating Fluidized Bed

Through the use of a charge coupled device's function of fast image acquisition on a self designed and built test rig obtained were the images of flow conditions in a fluidized bed under different airflow rates, followed by an effective processing of these initial images by using an image processing method. Furthermore, a series of phenomena were studied, including the turn down flow adhered on a wall, gas local diffusion coefficient, the profile of local voidage along the longitudinal and transverse axis, and the ascending velocity of bubbles. Also given is the fractal dimension of the boundary curve of bubbles during tests. As a result of the above, realized was the visualization of gas solid dual phase hydrodynamic characteristics in a circulating fluidized bed, thus fulfilling a fruitful attempt to use image processing techniques on a circulating fluidized bed.