| dc.description.abstract | In this study, a rectangular glass chute with a length of 1.5 meters, a width of 0.1 meters, and a height of 1.0 meters was used, and a pneumatic cylinder was used to inhale the baffles quickly to allow the pre-filled particle columns to simulate a dam break experiment, under almost the same initial aspect ratio of the particle stacking column, using cylinders of different lengths and changing the content ratio of the column to investigate the impact of the particle collapse flow on the state of motion and fluidity. In order to observe the movement changes at each characteristic time point of the particle collapse, use a high-speed camera and use PIV technology (Particle image velocity) to observe the movement changes of the particle collapse flow and the difference in the velocity profile at each characteristic time point.
When only a small amount of cylindrical particles are contained, the particle area is reduced because the spherical particles are replaced by cylindrical particles, but due to the small number of cylindrical particles, the distance from each other is far away, and the characteristics of the particles′ mutual traction are not obvious, and because the existence of cylindrical particles destroys the stable structure of the particle accumulation, resulting in a lubrication effect, so that the collapse distance is longer, and the fluidity becomes better, In the 8mm experiment, when the cylindrical particle content is 5%, there is the farthest collapse distance, while in the 12mm experiment is 25%.; but if the cylindrical particles continue to increase, the characteristics of cylindrical particles pulling each other will become more obvious, which will cause fouling effect instead, shorten the collapse distance and make the fluidity worse. In terms of analysis, the particle flow velocity profile of a vertical section (δL/3+Li) is used to discuss the velocity change of the particle collapse, and to observe the fluidity of the particle collapse flow by changing the proportion of the column content. | en_US |