Numerical Evaluation of Phase Change and Chemical Reactions on the Behavior of Cavitation Bubbles

In this paper a computer program is developed in order to investigate the effect of non equilibrium evaporation and condensation of water vapor at the bubble wall and that of chemical reactions of gases and vapor inside a bubble. Bubble instantaneous radius was obtained using Gilmore equation which considered the compressibility of the liquid. Pressure inside the bubble is calculated using the Van der Waals equation. The Hertz-Knudsen model is employed for modeling the evaporation and condensation of water molecules at the bubble wall. Numerical analysis is done for bubble in acoustic cavitation condition. With change the bubble inner gas type and decreasing bubble oscillation frequency، results have been developed for hydrodynamic cavitation. Numerical results show that for high driving pressure frequencies، the modeling phase change does not a significant effect on the bubble behavior. But by decreasing driving frequency the maximum bubble temperature decreases. It is also clarified that most of all the vapor molecules undergo chemical reactions at the strong collapse.