Experimental research on the effect of air bubble properties on aluminum cavitation erosion

Cavitation has been proven to cause damage to hydraulic structures. In recent times, aeration has been receiving increasing attention as a suitable method for preventing or reducing the erosion effects of cavitation. In this study, an orifice with a micrometer-sized diameter was designed for introducing air bubbles in water to examine the reduction in erosion caused by cavitation in ultrasonic environments. The experimental results showed that cavitation erosion is significantly reduced by low air concentration, which also reduces structural damage due to cavitation. At a certain air concentration level, the erosion reduction effects of the material do not change when the conditions of the air are altered, and the wall surfaces are protected by aeration and corrosion reduction; the air bubble frequency also influences cavitation erosion, with a high air bubble frequency resulting in a more conducive environment for minimizing cavitation damage. The influence of cavitation damage under the same aeration concentration and different air bubble sizes was also analyzed. The analysis results indicated that the combination of air concentration that satisfies the corrosion reduction requirements and smaller bubble size is highly advantageous for achieving the aeration and corrosion reduction effect at a smaller aeration concentration. Therefore, the aeration and corrosion reduction effect can be effectively achieved through the size of the bubble, and, in water conservancy projects, it can be beneficial for designing and analyzing methods to reduce corrosion and aeration.