空泡群溃灭过程中能量传递及溃灭压力产生机理研究

From the aspect of engineering application, on one hand, the negative effects, including noise and structural damage which caused by cavitation instability and collapse, are the main problems in high-speed underwater propulsion. On the other hand, people are also actively utilize the effects of cavitation and collapse: using ultrasound to generate repeated cavitation and collapse for lithotripsy and cleaning， and using bubbly flow to impact the material for surface strengthening. Understanding the microscopic mechanism of the collapse of cavitation and the formation mechanism of collapse pressure, whether it is to suppress the collapse of cavities or to better utilize collapse, is a key problem that cannot be ignored. This project is focused on the generation mechanism of collapse pressure and analyzes the interactions between bubbles during collapse from the point of view of energy. A compressible multiphase numerical simulation method with phase change effect and a controllable laser-induced bubble experimental method are developed to study the energy distribution and propagation of the collapse of bubbles under different conditions. Then a mathematical model of energy propagation during the multi-bubble collapse process is established to better explain the “energy focusing effect” and predict the collapse pressure during the collapse of bubble cluster.

从工程应用上来说，一方面空化不稳定性和溃灭带来的噪声、结构破坏等负面效应，是水下高速航行体和高速推进器面临的主要问题。另一方面，人们也在积极利用空化的溃灭效应：利用超声产生重复的空化和溃灭来碎石、清洁；利用空泡流冲击材料来进行表面强化。掌握空泡溃灭的微观机制和溃灭压力的形成机理无论是抑制空泡溃灭还是更好的利用溃灭都是难以避开的关键问题。本项目以空泡群的溃灭过程为研究对象，以理论分析和数值计算为主、实验为辅，以空泡相互作用为桥梁，从能量的角度研究微观空泡群溃灭压力的产生机制与物理模型。发展包含相变的可压缩多相精细化数值模拟方法和可控激光诱导空泡实验方法，研究空泡群溃灭过程中空泡间的能量传递机制、主控影响参数及其影响规律，并依此建立一套能够反映空泡分布和空泡间相互作用的空泡群溃灭数学模型，解释空泡群溃灭过程中的“能量聚集效应”并预测产生的溃灭压力。

从工程应用上来说，一方面空化不稳定性和溃灭带来的噪声、结构破坏等负面效应，是水下高速航行体和高速推进器面临的主要问题。另一方面，人们也在积极利用空化的溃灭效应：利用超声产生重复的空化和溃灭来碎石、清洁；利用空泡流冲击材料来进行表面强化。掌握空泡溃灭的微观机制和溃灭压力的形成机理无论是抑制空泡溃灭还是更好的利用溃灭都是难以避开的关键问题。本项目以空泡群的溃灭过程为研究对象，以理论分析和数值计算为主、实验为辅，以空泡相互作用为桥梁，从能量的角度研究微观空泡群溃灭压力的产生机制与物理模型。发展包含相变的可压缩多相精细化数值模拟方法和可控激光诱导空泡实验方法，研究空泡群溃灭过程中空泡间的能量传递机制、主控影响参数及其影响规律，获得不同气泡分布对泡群溃灭速率和溃灭压力的影响规律，获得空泡在不同条件下溃灭时的能量分布和传递规律，建立多空泡溃灭过程中能量传递的数学模型，解释并预测空泡群溃灭过程中的“能量聚集效应”。