Interaction between Micro-Particales and Bubbles in Cavitation-Erosion of Hydro-Machinery

Abstract

The cavitation-erosion is induced by the collapse of bubbles in the water. In the cavitation-erosion of hydro-machinery, it is generally accepted that the collapse of bubbles in water is attributed to the sharp rise of the pressure induced by the fluctuation of the fluid. However, it is proposed in this research that the collapse of bubbles is attributed to the interaction between micro-particles and bubbles in fluid. The cavitation -erosion experiments conducted in a rotating-disc flow shows that the most of micro-particles suspended in the water were damaged by the collapse of bubbles after cavitation-erosion, and played indispensable roles to induce the collapse of bubbles in the fluid. In the experiments, damage of the micro particles was evaluated by a transimission electron microscope (TEM) and the collapse of bubbles was estimated by the erosion pits on the solid surface.