| Summary: | 碩士 === 國立屏東科技大學 === 機械工程系 === 93 === This study investigated the wall stresses and flow patterns in a moving granular filter bed with a curved louvered-wall, and magnetic particles motion. The variations in the dynamic wall stresses with time were obtained using a pressure gauge which could simultaneously measure the normal of the granular solids. A digital camcorder was used to record the flow pattern histories of the granular solids in the moving granular filter bed. The numerical predictions of the flow patterns were implemented using DEM, and compared with the experimental results. The effects of the curvature of louvered-wall and the exit width upon the flow patterns and the wall stresses were also elucidated. For a fixed value of radius of curvature, the ratio of Q-S Z. area in the third stage to the granular bed area in the third stage increases with decreasing the width of the exit, but the average dynamic normal stress on the curved louvered-wall increases with increasing the width of the exit. For a fixed value of exit width, both the ratio of Q-S Z. area in the third stage to the granular bed area in the third stage and the average dynamic normal stress on the curved louvered-wall increases with increasing the radius of curvature. Additionally, the curved louvered-wall not only shrink the area of Q-S Z. in the granular bed but also reduce the dynamic nor-
mal stress on the louvered wall. The numerical predictions of the paths for two magnetic particles are conducted. When the angle of left particle between the easy axis of magnetization and the vertical line is large than 90°, two magnetic particles will stick together. The repulsive force increases with decreasing the angle. Furthermore, two magnetic particles in magnetic field fall more quickly than those without magnetic field.
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