球形颗粒对固体壁面附近激光诱导空化泡射流行为影响的实验研究1)
EXPERIMENTAL INVESTIGATION OF THE INFLUENCES OF THE SPHERICAL PARTICLE ON THE JET FORMATION OF THE CAVITATION BUBBLE NEAR THE SOLID BOUNDARY1)
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摘要: 依托高速摄影系统,本文探析了固体壁面和单个球形颗粒附近激光诱导空化泡溃灭过程中的射流行为。在实验过程中,主要对空化泡与颗粒间的无量纲距离以及空化泡与固体壁面间的无量纲距离进行了精确控制。基于高速相机所捕捉到空化泡完整动力学 过程的图片和数据,发现无量纲数\alpha (空化泡\!-\!颗粒无量纲距离与空化泡\!-\!固体壁面无量纲距离间的比值,表征空化泡在固体壁面与颗粒附近的相对位置)对实验结果有着较为显著的影响,并基于此对实验结果进行了定性和定量分析。分析结果表明:(1)与无颗粒的情况进行对比,颗粒的存在使空化泡溃灭时的射流方向产生偏移,且\alpha越小,其所对应的射流方向的偏移程度越大。(2)当\alpha较小时,空化泡沿颗粒表面向壁面方向发生显著移动。Abstract: Based on a high-speed camera system, this paper investigates the jet formation of the cavitation bubble during its collapse between the solid boundary and the spherical particle. During the experiment, the two parameters (the non-dimensional distance between the bubble and the particle, and the non-dimensional distance between the bubble and the solid boundary) are carefully controlled. Through the analysis of the photos and the data collected during the cavitation dynamic oscillations by the high-speed camera, it is found that the non-dimensional parameter \alpha (the ratio between the aforementioned two distances, representing the relative position of the bubble near the solid boundary and the particle) is a key influencing factor determining the phenomenon, in the quantitative and qualitative analyses. Our analysis reveals that: (1) unlike the case without the particle, the presence of the particle could alter the jet direction significantly during the bubble collapse and the alternation of the jet increases with the decrease of \alpha; (2) for small \alpha, the bubble makes a significant movement along the particle interfaces.