Study of Venturi tube geometry on the hydrodynamic cavitation for the generation of microbubbles
Study of Venturi tube geometry on the hydrodynamic cavitation for the generation of microbubbles
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DOI：
10.1016/j.mineng.2018.11.001
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发表时间：
2019-03-01
影响因子：
4.8
通讯作者：
Liu, Qingxia
中科院分区：
文献类型：
--
作者：
Li, Mingda;Bussonniere, Adrien;Liu, Qingxia
文丘里管已被广泛用于通过水力空化产生微气泡。由于其简单灵活的设计，文丘里管已被广泛应用于包括矿物浮选在内的各种应用中。尽管在不同的具体情况下，文丘里管的几何形状对水力空化的影响已经被研究过，但空化与文丘里管的几何参数之间的关系尚未见报道。在这项工作中，我们通过数值和实验研究了几个几何参数对水听器检测到的空化起始和高速相机测量到的微气泡产生的影响。利用无量纲数分析发现，空化起始是由流动阻力决定的，而流动阻力在很大程度上取决于文丘里管的几何设计。在空化状态下，空化引起的流阻随下游空化数的减少而线性增加，而上游空化数保持不变，与文丘里管的几何形状无关。较小的出口角度会导致较低的空化起始时间和较高的微气泡产量。此外，微气泡的产生程度随着额外流动阻力和溶解气体浓度的增加而增加。本研究为水力空化系统中高效文丘里管的设计提供了指导。
Venturi tubes have been extensively used to generate microbubbles through hydrodynamic cavitation. Due to their simple and flexible design, Venturi tubes have been used in a wide range of applications including mineral flotation. Although the impacts of the geometries of Venturi tubes on hydrodynamic cavitation have been studied in different specific contexts, no clear relation between cavitation and geometry parameters of Venturi tubes has been reported. In this work, we investigated numerically and experimentally the influence of several geometrical parameters on the cavitation inception detected by a hydrophone and the microbubble generation measured by a high-speed camera. Using a dimensionless number analysis, we found that the cavitation inception was determined by flow resistance, which significantly depends on the geometrical design of Venturi tube. In the cavitation regime, the flow resistance induced by cavitation increases linearly with reducing downstream cavitation number while the upstream cavitation number becomes constant regardless of the geometry of Venturi tube. A small outlet angle results in a low cavitation inception and a high microbubble production. Moreover, the degree of microbubble generation was found to increase with extra flow resistance and the dissolved gas concentration. The insights from this study provide a guideline for the design of efficient Venturi tubes for hydrodynamic cavitation system.