Abstract:

This study investigated fluidization experiments of wood particles with five different aspect ratios (AR=1—5) in a rectangular fluidized bed. The total pressure and sectional pressure drops were measured, and the fluidization behavior of different wood cylinders was recorded using high-speed photography. An image processing method was employed to analyze the height and orientation distribution of cylindrical particles at different gas velocities. The results demonstrated that wood cylinders with aspect ratios below 5 could achieve complete fluidization in the rectangular fluidized bed, whereas significant channel flow occured for cylindrical particles with AR=5, making them difficult to fluidize. The study revealed that AR significantly affected both the sectional pressure drop distribution and the minimum fluidization velocity, with the blocking effect of cylindrical particles becoming more pronounced as AR increased. Furthermore, when fully fluidized, wood cylindrical particles with different AR values tended to align their axial direction with the gravity direction. These experimental results and observed channel flow could provide fundamental data for validating and understanding gas-solid systems using computational fluid dynamics simulations.

Key words: fluidization, cylindrical particles, pressure drop, height distribution, orientation distribution, image processing

摘要：

对矩形流化床中5种不同长径比（AR=1~5）的柱形颗粒进行流态化实验，测量了床层总压降和分段压降分布。通过高速摄像机拍摄不同柱形颗粒的流态化视频，采用图像处理方法分析了不同气速下柱形颗粒的高度和转角倾向分布。实验结果表明，在矩形流化床中，长径比小于5的柱形颗粒能够完全流化，而AR=5的柱形颗粒通道流现象显著且难以流化。AR会影响分段压降分布以及最小流化速度，柱形颗粒的堵塞作用随着AR的增大而增强。不同AR的柱形颗粒在完全流化后，其轴向趋于与重力方向一致。本文的实验数据以及观察到的通道流现象可为气固系统中计算流体动力学模拟的验证和研究提供基础数据。

关键词: 流态化, 柱形颗粒, 压降, 高度分布, 转角分布, 图像处理