The Dynamic Evolution of Cavitation Vacuolar Cloud with High-Speed Camera

Abstract

The dynamic model of a single cavitation bubble in the submerged cavitation water jet was established and solved by MATLAB to obtain its motion characteristics and pressure pulse change rules. Numerical simulation based on FLUENT to closer wall, empty bubble breaking form then influences the law of mechanics effect, with the increase in empty bubble, and the breaking time is reduced, but the maximum jet velocity and pressure increase gradually, on the mechanism of action of the solid wall by the fact that the combination of microfluidic and shock wave gradually plays a leading role, while plastic deformation and basic cavitation erosion are avoided. The maximum pressure and maximum jet velocity increase little, and the collapse time of cavitation is reduced. By comparing the grayscale images of the two combinations of jets, it can be found that the brightness of the vacuolar clouds in diameter (d) = 1.6 mm and pressure (P) = 15 MPa is slightly less than that in d = 1.2 mm and P = 30 MPa, indicating that the density of the vacuolar clouds and the dispersion is relatively high, while the increase in nozzle diameter leads to the increase in flow rate, which increases the shear layer of high-speed submerged jet in a static water. The pressure pulse generated by cavitating water jet hollow bubble failure is far greater than the linear superposition value of a single cavitation bubble. But the high-pressure shock wave value on the fixed wall and water hammer pressure are generated by microjet. The conclusion is also corresponding to the simulation results.