Influence of Internal Phenomena on Gas Bubble Motion

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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.