ABSTRACT

Cavitation erosion is a fundamental concern in many fields of engineering, e.g. the flow separation zone in high speed flow and the blade area of hydraulic machinery. However, the influence of the physical characteristics of the environmental medium in these engineering facilities on cavitation erosion is still unclear. In this paper, we adopted underwater low-voltage discharge technology to generate cavitation bubbles, and studied the mesoscale causes of material erosion in solutions with different surface tensions. It is found that with the decrease of liquid surface tension, the radial velocity of cavitation bubbles decreases significantly during the shrinkage of the cavitation bubble and the minimum radius to which the cavitation bubble shrinks increases, the micro-jet generated by the cavitation bubble develops more slowly, and the impact strength of cavitation bubble collapses on the wall decreases. The findings reveal new physical mechanisms of the cavitation-induced material erosion in liquids with different surface tensions at the macroscopic level. These will provide significant guidance for cavitation prevention in various applications such as aeration cavitation-alleviation, hydraulic machinery, ultrasonic cleaning and the medical industry.

摘要

气蚀是许多工程领域的基本问题，例如高速流动中的流动分离区和液压机械的叶片区域。然而，这些工程设施中环境介质的物理特性对空蚀的影响尚不清楚。本文采用水下低压放电技术产生空化气泡，研究了不同表面张力溶液中材料侵蚀的中尺度原因。研究发现，随着液体表面张力的降低，空化泡收缩过程中空化泡的径向速度显着降低，空化泡收缩的最小半径增大，空化泡产生的微射流更加发达。慢慢地，空化泡破裂对壁面的冲击强度降低。研究结果揭示了在宏观水平上具有不同表面张力的液体中空化引起的材料侵蚀的新物理机制。这些将为各种应用中的气蚀预防提供重要的指导，例如曝气气蚀缓解、液压机械、超声波清洗和医疗行业。