Cavitation erosion of a single bubble in water as a kind of dynamic damage

摘要

In this study, a rotating disk test rig was used for the cavitation test of the brass samples. A pit of single black dapple and a large pit of multiring black dapple were found on the sample surfaces after 30 h test. A cavitation model of the rotating disk test was further developed by applying a periodic water pressure into the Keller-Miksis equation, so as to obtain the bubble dynamic characteristics. A comparison with the available experimental results reveals that the velocity of the bubble wall is governed by the initial bubble radius, and the bubble collapsing mode has changed from single bubble compression with high velocity to multiple bubble compression, with a increase in the initial bubble radius. The results also show that the movement of the spherical bubble wall induces the formation of the micro-jet with high velocity, leading to cavitation erosion pits on the specimen surface in the rotating disk test, which are well verified by the present theoretical model as well as the available experimental results.