• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Granular matter >Transient behavior of granular materials as result of tumbler shape and orientation effects
【24h】

Transient behavior of granular materials as result of tumbler shape and orientation effects

机译：不倒翁形状和取向效应导致颗粒状材料的瞬态行为

获取原文
获取原文并翻译 | 示例
       
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Granular flows are most often investigated at steady-state conditions. This allows time-averaged analysis to display results such as velocity profiles and convec-tive accelerations within the thin flowing layer. Typically in rotating tumblers, constant rotation rates and circular shapes are used as they jointly produce a steady, uniform flowing layer at the free surface. Conversely, unsteady flowing layers can be generated through any combination of varying the rotation rate of a tumbler or using a non-circular cross-sectional shape to change the length of the flowing layer. The unsteady conditions, however, require the additional complexity of ensemble-averaged analysis of images in a sequence of multiple trials. The experiments of this paper examine the properties of unsteady flow produced by triangular-shaped rotating tumblers at constant rotation rates. The geometric shape naturally causes periodic changes in the flowing layer as a function of the instantaneous orientation of the triangle. Multiple experiments were conducted in which the parameters of tumbler dimension, particle size, fill level and rotation rate were varied in all combinations. The free surface properties of angle of repose and flowing layer length, position, and curvature are reported. Results show that the arithmetic difference between the angle of repose and the tumbler orientation has a functional relationship with the instantaneous flowing layer length in the form of a catenary indicating a minimization of energy in the granular flow. Furthermore, the oscillation of the flowing layer position appears to affect the free surface curvature in the upstream regions. This is likely due to the rapidly increasing and decreasing length of the free surface limiting the space where particles can enter or exit the flowing layer. Ultimately, the unsteady macroscopic properties of the free surface flowing layer in the triangular tumblers provide some indication of the complexities of granular velocity and acceleration that contribute to the mixing and segregation in this unique tumbler shape.
机译：最经常在稳态条件下研究颗粒流。这允许时间平均分析显示薄流动层内的速度曲线和对流加速度等结果。通常在旋转的玻璃杯中，使用恒定的旋转速度和圆形形状，因为它们共同在自由表面上产生稳定，均匀的流动层。相反，不稳定的流动层可通过改变制杯机的旋转速率或使用非圆形横截面形状改变流动层的长度的任何组合来产生。然而，不稳定的条件要求在一系列多次试验中对图像进行整体平均分析的额外复杂性。本文的实验研究了三角旋转杯在恒定转速下产生的非定常流动特性。几何形状自然会导致流动层中的周期性变化，该变化是三角形的瞬时方向的函数。进行了多个实验，其中，在所有组合中，不倒翁尺寸，粒径，填充水平和转速的参数均发生了变化。报告了休止角和流动层长度，位置和曲率的自由表面特性。结果表明，休止角和制动栓取向之间的算术差与悬链形式的瞬时流动层长度具有函数关系，表明颗粒流中的能量最小。此外，流动层位置的振荡似乎会影响上游区域的自由表面曲率。这可能是由于自由表面长度的快速增加和减少限制了颗粒可以进入或离开流动层的空间。最终，三角杯中的自由表面流动层的不稳定的宏观特性提供了颗粒速度和加速度的复杂性的某种指示，这些复杂性有助于这种独特的杯形混合和分离。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号