Effect of NaCl and CO2 on the inception control of hydrodynamic cavitation by gas solubility change

Abstract

Hydrodynamic cavitation is a common natural phenomenon that has positive and negative implications in several fields. In one hand, it is a major cause of corrosion and noise radiation in the marine industry. On the other hand, it is used as an innovative process for enhancing mineral flotation and water disinfection. Therefore, understanding the promotion and prevention mechanisms of hydrodynamic cavitation inception is essential for industrial applications. In this study, a Venturi tube was used as the hydrodynamic cavitation device, and the cavitation inceptions were measured using the sound-detection method. NaCl was shown to promote cavitation inception of water. However, no obvious change was observed for air-saturated NaCl solutions. These results are explained by the increase in air saturation level when salt is added into water. Based on this idea, the cavitation inception can be controlled by modifying the CO2 solubility through changing the pH of carbonated water, a process that was shown to be reversible. These findings are applicable to industrial operations that try to avoid cavitation or those where the generation of bubbles is required.