| Cavitation is a special dynamic phenomenon happened in liquid region where the local pressure is lower than the saturated vapor pressure at ambient temperature.With the development of computational fluid dynamics and rapid improvement of computer operation capacity, it has been possible to research the inner fluid flow inside fluid machinery by way of numerical simulation. Numerical simulation can estimate the parameters that are difficult to measure in experiment. In the analysis and engineering design process of fluid machinery, the numerical simulation improves reliability and reduces the cost significantly. Numerical method has become an important tool to design fluid machinery.Based on hydromechanics computation knowledge, taking commercial CFD software Fluent as tool, using Volume of Fluid (VOF) model and unsteady method to solve the Navier-Stokes equations to simulate the bubble collapse process near or on the solid wall, the effects of liquid viscosity and surface tension on bubble collapse process are performed in the present thesis. It was investigated the collapse time and liquid-jet pressure of the bubbles in case of the fluids with different physical properties (viscosity and surface tension). The results showed that the following micro jet might cause high pressure domain on the solid wall to induce the cavitation erosion based on the water hammer theory. The viscous force decreases bubble growth and collapse process, makes it expand or collapse less violently. The bubble collapse time increased with the fluid viscosity; However, the liquid-jet pressure decreased with the increase of the fluid viscosity. Surface-tension forces stave bubble growth progress and speeds up the bubble collapse process. Thus, higher surface-tension increases the liquid-jet pressure and produces higher erosive power.These results are valuable in the field of cavitation erosion and provides a platform for the numerical calculation on the cavitation erosion.
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