扩大石灰石粉动态和准静态流动试验的范围
Stretching the limits of dynamic and quasi-static flow testing on limestone powders
摘要：
由于cohesion内聚力的重要作用，粉末是一类特殊的颗粒物质。粉末的流动行为取决于流动状态和应力，因此难以仅通过一个实验来测量/量化。在这项研究中，最常用的表征测试，涵盖了广泛的状态进行了比较：（静态，自由表面）的休止角，（准静态，限制）环剪切稳态角的内摩擦，和（动态，自由表面）旋转鼓流角被认为是自由流动，适度和强烈的凝聚力石灰石粉末。自由流动的粉末在所有不同的情况（设备）之间提供良好的一致性，而中等和强粘性的粉末表现得更有趣。从转鼓中的流动角开始，并且变慢，可以外推到零转速的极限，但是随后观察到从堆测量的休止角相当大，这可能是由于其特殊的历史。当我们拉伸环剪试验到其最低的侧限应力时，粘性粉末的稳态内摩擦角与零转速极限下的流动角（在自由表面处）一致。
英文摘要：
Powders are a special class of granular matter due to the important role of cohesive forces. The flow behavior of powders depends on the flow states and stress and is therefore difficult to measure/quantify with only one experiment. In this study, the most commonly used characterization tests that cover a wide range of states are compared: (static, free surface) angle of repose, the (quasi-static, confined) ring shear steady state angle of internal friction, and the (dynamic, free surface) rotating drum flow angle are considered for free flowing, moderately and strongly cohesive limestone powders. The free flowing powder gives good agreement among all different situations (devices), while the moderately and strongly cohesive powders behave more interestingly. Starting from the flow angle in the rotating drum and going slower, one can extrapolate to the limit of zero rotation rate, but then observes that the angle of repose measured from the heap is considerably larger, possibly due to its special history. When we stretch the ring shear test to its lowest confining stress limit, the steady state angle of internal friction of the cohesive powder coincides with the flow angle (at free surface) in the zero rotation rate limit.
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