Influence of a Non-Condensable Gas Admixture Inside a Vapor Bubble on Its Collapse

The collapse of a vapor (steam) bubble in liquid (water) at room conditions is considered. Initially the bubble is filled with the saturated vapor and some quantity of non-condensable gas (air) admixture at the temperature of water, which is typical for real bubbles. Main attention is focused on investigating the dependence of the bubble collapse on the presence of the gas admixture. The initial mass of the admixture is varied, whereas the vapor mass is kept constant. In the bubble dynamics model used, the bubble content is treated as homobaric, the liquid as weakly compressible, and the vapor and the gas admixture as perfect gases. These assumptions are validated by comparison with available numerical results by the models without such simplifications. It has been shown that with the presence of a small initial mass fraction (less than 10 $$\%$$ ) of the gas admixture inside the vapor bubble, the bubble quite rapidly (after a few rebounds) turns into a predominantly gas bubble. With increasing the initial fraction of the gas admixture, the transition lasts longer, the amplitude of the rebounds grows, their frequency decreases. The collapse of the bubble becomes weaker, so that the maximum pressure and temperature in it are reduced by more than $$6.5$$ and $$1.5$$ times, respectively. If the diffusion in the bubble is ignored, the bubble collapse is much weaker. The effect of increasing the accommodation coefficient is to some extent similar to that of increasing the initial fraction of the gas admixture.