Experimental study on the mesoscale causes of the effect of sediment size and concentration on material cavitation erosion in sandy water

Abstract The cavitation erosion of materials in sandy water is a very important topic in water conservancy and industrial production. In this paper, an ultrasonic vibration cavitation apparatus and underwater low-voltage electric discharge device are applied to investigate the erosion characteristics of 6063 aluminium specimens in sandy water with different sediment sizes and concentrations and the underlying mesoscale damage mechanism. The results show that the specimen damage gradually increases as the mean sand particle size increases. When the mean sand particle size is less than 0.120 mm, the resulting damage is lower than that in pure water. When the sand concentration is less than 10 kg/m3, the resulting damage is not very different from that in pure water. As the sediment concentration in the sand-water mixture increases, the influence of the sand particles on cavitation gradually increases. The bubble-particle interaction experiments reveal that the cavitation bubbles that interact with multiple small spherical particles show obvious non-spherical morphology and prolong the collapse time during the first collapse phase and reduce the collapse strength. The results of the bubble-particle interaction experiments verify the erosion characteristics obtained from the ultrasonic vibration cavitation test, which is significant for elucidating the damage mechanics of specimens in sandy water.