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arXiv 0907.4871cond-mat.softcond-mat.stat-mech
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振动在筒仓卸粮过程中的作用

Role of vibrations in the jamming and unjamming of grains discharging from a silo

Cristian Mankoc, Angel Garcimartin, Iker Zuriguel, Diego Maza, Luis A. Pugnaloni

摘要:

本文介绍了在垂直振动作用下,平底筒仓卸料时无粘性颗粒堵塞的实验结果。当出口孔仅为几个颗粒直径宽时,由于阻塞拱的形成,流动可以被阻止。因此,需要外部激励来恢复流动。在这种情况下,使用连续的轻微振动是缓解流动的常用技术。即使堵塞不那么频繁,它仍然是振动筒仓中的一个问题。原则上,有两种可能的机制,通过振动可以促进流动:(i)减少阻塞拱形成的可能性,以及(ii)一旦阻塞拱形成,阻塞拱就会破裂。通过测量雪崩内部没有颗粒流过出口的时间间隔,我们能够估计振动破坏阻塞拱的概率。这一结果与双变量概率模型的预测一致,在该模型中,振动和非振动筒仓中形成阻塞拱的可能性相等。这表明,上述第二种机制是改善轻微振动筒仓流动性的主要原因。

英文摘要:

We present experimental results of the jamming of non-cohesive particles discharged from a flat bottomed silo subjected to vertical vibration. When the exit orifice is only a few grain diameter wide, the flow can be arrested due to the formation of blocking arches. Hence, an external excitation is needed to resume the flow. The use of a continuous gentle vibration is a usual technique to ease the flow in such situations. Even though jamming is less frequent, it is still an issue in vibrated silos. There are, in principle, two possible mechanisms through which vibrations may facilitate the flow: (i) a decrease in the probability of the formation of blocking arches, and (ii) the breakage of blocking arches once they have been formed. By measuring the time intervals inside an avalanche during which no particles flow through the outlet, we are able to estimate the probability of breaking a blocking arch by vibrations. The result agrees with the prediction of a bivariate probabilistic model in which the formation of blocking arches is equally probable in vibrated and non-vibrated silos. This indicates that the second aforementioned mechanism is the main responsible for improving the flowability in gently vibrated silos.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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