Abstract Shaul & Kalman (2014–2015) defined three different types of plugs (Plug-I, II and III) of different particulate materials for dense phase pneumatic conveying. The Present experimental study is undertaken to determine the borderline between Plug-I and the other type of plugs. The borderline is established by using the concept of detachment velocity of the particles from the front of the plug. For the current study, thirty three particulate materials have been tested having the Archimedes number (Ar) in the range of 10− 3 to106. The experiments conducted in three transparent Plexiglas pipes of diameters 1 in., 2 in. and 3 in. For each experiment, a single artificial plug of type I of varying length in the range of 10–100 cm was inserted into the test section of 1.5 m length. Further, as the plug flow is a low velocity phenomenon, the Reynolds number (Re) during experimentation, is varied in the range of 10− 3 to 102. The results of the experiments show that for the particulate materials with Ar > 102, first the phenomenon of detachment occurs at a corresponding velocity and on further increasing the flow rates the plug dissembled. The variation of the detachment velocity is found to be a power function of the Ar number (for Ar > 102), whereas, the detachment velocity is found to be independent of the pipe diameter and plug length. For materials with Ar

中文翻译：

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脱离速度：不同类型颗粒塞之间的分界线

摘要 Shaul & Kalman (2014–2015) 定义了用于密相气力输送的不同颗粒材料的三种不同类型的塞子（Plug-I、II 和 III）。本实验研究是为了确定 Plug-I 和其他类型的插头之间的界限。边界线是通过使用粒子从塞子前端脱离速度的概念来建立的。对于当前的研究，已经测试了 33 种颗粒材料，其阿基米德数 (Ar) 在 10-3 到 106 的范围内。在三个直径分别为 1 英寸、2 英寸和 3 英寸的透明有机玻璃管中进行实验。对于每个实验，将一个长度在 10-100 厘米范围内变化的 I 型人工塞插入1.5 m 长。此外，由于活塞流是一种低速现象，实验过程中的雷诺数（Re）在 10-3 到 102 范围内变化。 实验结果表明，对于 Ar > 102 的颗粒材料，首先在相应的速度下发生分离现象，然后进一步增加塞子拆卸的流速。发现分离速度的变化是 Ar 数的幂函数（对于 Ar > 102），而分离速度与管道直径和塞子长度无关。对于含 Ar 的材料 发现分离速度的变化是 Ar 数的幂函数（对于 Ar > 102），而发现分离速度与管道直径和塞子长度无关。对于含 Ar 的材料 发现分离速度的变化是 Ar 数的幂函数（对于 Ar > 102），而分离速度与管道直径和塞子长度无关。对于含 Ar 的材料