含气泡液体中气泡振动的研究

研究了含气泡液体中单个气泡在驱动声场一定情况下的振动过程. 让每次驱动声场作用的时间特别短, 使气泡半径发生微小变化后再将其变化反馈到气泡群对驱动声场的散射作用中去, 从而可以得到某单个气泡周围受气泡散射影响后的声场, 接着再让气泡在该声场作用下做短时振动, 如此反复. 通过这样的方法, 研究了液体中单个气泡的振动情况并对其半径变化进行了数值模拟, 结果发现, 在液体中含有大量气泡的情况下, 某单个气泡的振动过程明显区别于液体中只有一个气泡的情况. 由于大量气泡和驱动声场的相互作用, 使气泡半径的变化存在多种不同的振动情况, 在不同的气泡大小和含量的情况下, 半径变化过程分别表现为: 在平衡位置附近振荡的过程; 周期性的空化过程; 一次空化过程后保持某一大小振荡的过程; 增长后维持某一大小振荡的过程等. 所以, 对于含气泡液体中气泡振动的研究, 在驱动声场一定的情况下, 必须考虑气泡含量的因素. 关键词： 含气泡液体 超声空化 散射 数值模拟

Vibration of the bubble in bubbly liquids

The vibration of bubbles in bubbly liquids has been studied when the driving sound field is fixed. The radius of the bubble will change when the bubble is driven by a driving acoustic field for a short time. This small change of radius is then fed back to the scattering process of the bubbles driven by the driving acoustic field. Thus the compound acoustic field including the scattered field of the bubble can be obtained. Then the bubble is again driven into vibration for a short time. By repeating the same procedure, the bubble vibration and its radius variation are simulated by a numerical method. It is shown that in the case of numerous bubbles in the liquid the vibration of a bubble is different from the case of only a single bubble in it. Because numerous bubbles will show interactions between one another, the radius of the bubble will change in different manner. For different size and content of bubbles, the radius of the bubble changes according to the following rules. The radius will oscillate in the vicinity of the equilibrium position; the radius oscillation shows a periodic cavitation process; the radius will vibrate during one cycle of cavitation; then, the radius will increase and oscillate in the vicinity of a certain value. Therefore, it is necessary that the bubble content should be considered in analyzing the vibration of the bubble in a bubbly liquid under a driving sound field.
Keywords： bubbly liquids ultrasonic cavitation scattering numerical simulation