Influence of Internal Phenomena on Gas Bubble Motion

从分析和实验两个方面研究了内部现象对气泡运动的影响。在数值分析中，直接对气泡运动的控制方程进行积分，以估算内部现象对气泡运动的影响，如传热、气泡壁面相变、气体间扩散等，并计算了气泡在周围压力递增和递减时的运动。结果表明，蒸汽和不凝性气体之间的换热和扩散对气泡的运动有影响，当初始半径较大或降压比较小时，气泡膨胀时会产生雾，而雾的形成对气泡的运动有影响。在实验中，利用激波管研制了实验装置，研究了单个气泡在周围压力先减小后增大时的运动行为。进行了两种类型的实验。一个是气泡半径的测量。实验结果与数值计算结果吻合较好。另一种是检测气泡破裂时的光发射，气泡中含有少量的乙炔。并将计算结果与数值结果进行了比较。计算的气泡崩塌时间与探测到光发射的时间一致。将代表乙炔氧化诱导时间的关联式与数值结果进行了比较，结果表明，在分析气泡运动时，考虑内部现象是重要的。提出了一个简单的气泡运动模型，并将其应用于冲击波在稀泡液体中的传播。结果表明，气泡运动的热耗散对激波的分布有很大影响。

Influence of internal phenomena on gas bubble motion was investigated in analytical and experimental ways. In numerical analysis, the governing equations for the bubble motion were integrated directly in order to estimate the effect of internal phenomena, such as heat transfer , phase change at the bubble wall, diffusion among the gas and so on and the bubble motion was calculated when surrounding pressure increases and decreases stepwisely. The results reveal that heat transfer and diffusion between vapor and noncondensable gas give effects to the bubble motion and also show that mist appears when bubble expands and mist formation gives effects to the bubble motion as the initial radius is large or depressurization ratio is small. In the experiment, the experimental apparatus was developed by using the shock tube and the behavior of single bubble motion was investigated when the surrounding pressure decreases and then increases. Two kinds of experiments were performed. One is the measurement of the bubble radius. The results of experiment agree well with the numerical results. The other is the detection of the light emission when the bubble, which contains small amount of acetylene, collapses. The results were also compared with the numerical results. The calculated bubble collapsing time coincide with the time when the light emission was detected. The correlations which represent the induction time of acetylene oxidation was compared with the numerical result and the comparison shows that it is important to take the internal phenomena into account for analysis of the bubble motion. The simple model of the bubble motion was proposed and applied to propagation of the shock wave in dilute bubbly liquids. The result is that thermal dissipation of the bubble motion gives much effect to the profile of the shock wave.