当超声作用于装有液体的有限容器中时,液体中的气泡对超声辐射具有一定的阻尼作用.文中通过分析和比较流体中的超声声场分布,探讨气泡体积比对流体中超声声场分布的影响.结果表明,考虑空化泡在流体中引起的阻尼效应的计算结果与铝箔腐蚀实验结果比较相符,有限容器内流体中的气泡体积比对流体中的超声声场分布有重要影响.当流体中气泡体积比小于作用于流体中的超声波频率对应的阈值时,可以在稳态线性声波波动方程基础上作进一步计算以得出流体中的超声声场分布,否则计算结果与流体中的实际声场分布差异较大.
When the liquid in a vessel with limited volume is irradiated by ultrasonic, the bubbles in the liquid may cause a damping effect on the ultrasonic wave. In order to reveal the effect of the volume fraction of bubbles on the distribution of ultrasonic field in liquid, the distributions of ultrasonic field in liquid in different conditions are compared and analyzed. It is found that the calculated results considering the damping effect of ultrasonic cavitation bubbles accord well with the experimental ones of aluminum foil erosion in liquid, and that the bubble volume fraction has great effect on the distribution of ultrasonic field in liquid. It is also demonstrated that, when the bubble volume fraction is less than the threshold related to a given ultrasonic frequency in liquid, one can employ the method based on the static linear wave equation to calculate the distribution of ultrasound field in liquid. However, when the volume fraction exceeds the threshold, there exists a significant difference between the calculated results and the actual ones.