泡群内气泡振动特性分析  

Vibration characteristic of bubbles inside a spherical cluster

作　　者：王成会[1] 莫润阳[1] 胡静[1] 张明铎[1] WANG ChengHui MO RunYang HU Jing ZHANG MingDuo(Shaanxi Key Laboratory of Ultrasonics, Shaanxi Normal University, Xi＇an 710062, China)

机构地区：[1]陕西师范大学超声学重点实验室,西安710062

出　　处：《中国科学：物理学、力学、天文学》2017年第2期53-61,共9页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金(编号:11204168;11474191);中央高校基本科研业务费专项资金(编号:Gk201603102)资助项目

摘　　要：本文从均匀球状泡群内气泡非线性振动方程出发分析了驱动声压幅值、声波频率和液体环境对空化气泡振动特性的影响.数值分析结果表明:超声波驱动下的非线性振动气泡存在不稳定响应区,不稳定响应区主要分布在声波频率小于5 0 kHz的低频区和平衡半径小于1 0μm的微泡尺寸范围;平衡半径为3μm左右的空化微泡有较强的声响应能力和不稳定性,在特定的液体和声环境中,极易受到扰动生长为平衡半径更大的气泡;驱动声波频率一定的情况下,随着驱动声波压力的增加,气泡的非线性共振频率降低,声场中气泡的共振尺寸减小;平衡半径大的气泡空化阈值低,更容易引起空化效应.液体内溶解气体浓度影响空化进程以及空化声压阈值,溶解气体浓度越低空化阈值越高.The motion of a cavitation bubble can be affected by many factors,such as acoustic frequency,acoustic pressure,bubble sizes and liquid properties.Furthermore,the size distribution of bubbles in the cavitation liquid is influenced by the acoustic condition and liquid properties.It is important to control the size distribution of cavitation bubble because the oscillation of cavitation bubble is related to the cavitation intensity.According to the dynamic model of bubbles in a spherical bubble cluster,the oscillating behavior of bubbles has been studied numerically to evaluate the effect of the driving frequency,pressure amplitude and the liquid properties on the vibration characteristic of cavitation bubbles.The ratio of maximum radius to minimum radius for a oscillating bubble is investigated and the numerical results suggest that,the unstable acoustic response parameter region exists when the size of microbubbles is less than 10 μm and bubbles are drivenby acoustic wave whose frequency is lower than 50 kHz.Bubbles of 3（xm radii are more sensitive to the change of the acoustic parameters and vibrate more violently,and it is easy to grow up to a larger one because of the rectified mass diffusion.The nonlinear resonance of forced oscillating bubble can be observed on the response curves of bubbles,and it is found that the resonant frequency of bubbles decreases with the increment of the driving pressure amplitude.Therefore,a smaller resonant size of bubbles could be obtained in high-intensity ultrasound field.In a multibubble system,the nonlinear resonant response is mainly in the region that the acoustic frequency is smaller than the natural frequency of bubble and a microbubble smaller than the resonant one is easy to resonate with the acoustic condition although cavitation pressure threshold decreases with the size increment of cavitation bubbles.Based on the analysis of the effects of gas concentration on the bubble size distribution in the multibubble system,it is found that there are threshold and stable ra

关 键 词：球状泡群 空化气泡 振动特性 非线性共振 

分 类 号：O35[理学—流体力学]