摘要
根据考虑了液体可压缩性的改进的微气泡动力学方程,采用改进的初始半径对单泡超声空化现象进行了数值计算研究.结果表明,微气泡振动对一些参量很敏感:微气泡振动半径与初始半径的比值随振动频率的增大而减小;提高声场声压会加剧气泡崩塌程度,但过高的声压又不能使微气泡崩塌;微气泡崩塌速率随气泡初始半径的增加而增大,在一定范围内能保证空化泡稳定振动,在初始半径为1.6μm处空化程度最强,如果继续增大初始半径则空化程度减弱、甚至消失;微气泡崩塌程度随黏滞系数和表面张力的增大而减弱,过大的黏滞系数和表面张力会使微气泡崩塌难以发生.计算结果与他人的实验数据相比,发现液体的可压缩性使单泡空化强度增强,对最佳空化区域范围的确定有较大的影响.
In this paper, the ultrasonic cavitation phenomenon of single bubble is numerically investigated with an improved initial bubble radius associated with the improved dynamic equation （Rayleigh-Plesse equation） considering the effect of compressible of the micro-bubble. The numerical results indicate that the bubble vibration is very sensitive to some exciting parameters. Enhancing the ultrasonic signal frequency can decrease the vibration-initial radius ratio of the bubble. On the contrary, the collapse of bubble will become more violent with higher acoustic pressure, but overhigh pressure will make it never happen. With the increase of bubbles＇ original radius, the collapse velocity of the bubble becomes higher; the vibration of cavitation bubble can keep on a steady process in a range of initial bubble radius. The cavitation is strongest at the initial radius of 1.6μm, and will weaken or never happen when initial bubble radius keep on increasing. Enhancing liquid surface tension or viscosity can weaken the collapse of bubble, but the collapse is hard to occur when they become higher. A comparison between the numerical results and the published experimental data shows that the liquid compressibility has a great influence on the determination of zone boundaries of the best cavitation, and makes the cavitation intensity of single bubble stronger.
出处
《力学学报》
EI
CSCD
北大核心
2009年第1期8-14,共7页
Chinese Journal of Theoretical and Applied Mechanics
基金
浙江省自然科学基金(Y605312
Y1080959)
浙江省教育厅课题基金(20030704)资助项目~~
关键词
超声空化
空化气泡
微气泡动力学
最佳初始半径
ultrasonic cavitation, cavitation bubble, bubble dynamics, best original radius
