State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China.
State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China.
Ultrason Sonochem. 2019 Dec;59:104699. doi: 10.1016/j.ultsonch.2019.104699. Epub 2019 Jul 17.
Cavitation is a very important hydrodynamic phenomenon in many scientific and engineering fields, such as acoustics, medicine, and hydraulics. The relationship between the physical characteristics of liquid media and the erosion status of materials in a cavitation field is a crucial concern for many researchers. In this study, we adopted underwater low-voltage discharge technology to generate cavitation bubbles. We studied the effect of the viscosity of liquid media on cavitation bubble dynamics at the mesoscale level by using high-speed photography and a transient stress test system to illustrate the mechanism and the characteristics of material erosion under viscosity changes at the macroscopic level. It was found that high liquid viscosity delays shrinkage of the cavitation bubble and increases the minimum volume to which the cavitation bubble shrinks. The shrinkage characteristics of a cavitation bubble in a solution with high viscosity can reduce the speed of micro-jet formation during the collapse of the cavitation bubble near a wall. In addition, they can delay the impact of the micro-jet on the wall surface and reduce the impact strength when the cavitation bubble collapses. The effect of viscosity on cavitation bubble dynamics at the mesoscale level can explain the erosion law of solid-wall surfaces in a cavitation field from a mechanical point of view. These conclusions present significant potential for cavitation application and prevention in the fields of ultrasonic cleaning, medicine, and hydraulic machinery.
空化是许多科学和工程领域（如声学、医学和液压）中非常重要的流体动力现象。液体介质的物理特性与空化场中材料的侵蚀状态之间的关系是许多研究人员关注的关键问题。在本研究中，我们采用水下低压放电技术产生空化气泡。我们通过高速摄影和瞬态应力测试系统研究了液体介质粘度对空化气泡动力学的影响，从宏观水平上说明了材料在粘度变化下的侵蚀机制和特征。结果表明，高液体粘度会延迟空化气泡的收缩，并增加空化气泡收缩的最小体积。在靠近壁面的空化气泡塌陷过程中，高粘度溶液中空化气泡的收缩特性可以降低微射流的形成速度。此外，它们可以延迟微射流对壁面的冲击，并降低空化气泡塌陷时的冲击强度。粘度对空化气泡动力学的介观水平的影响可以从力学角度解释空化场中固壁表面的侵蚀规律。这些结论为超声清洗、医学和水力机械等领域的空化应用和预防提供了重要的参考价值。
