Effect of salted water temperature on dynamic process and collapse behavior of the cavitation bubble.

How to efficiently utilize cavitation to promote chemical reactions or degrade microorganisms is a concern in the fields of biological and chemical engineering. Changes in liquid temperature can affect bubble dynamics, thereby influencing chemical reaction rates or microbial degradation efficiency. This study used the method of corona discharge induced bubbles, combined with high-speed camera system and temperature control system, to investigate the effect of salted water temperature on the bubble collapse behavior in the free field and below the liquid surface. In the free field, it was found that salted water temperature affected the maximum radius, minimum first contraction radius, expansion time and collapse time of bubble. And the above parameters showed an increasing trend with the increase of salted water temperature. Further measurements using high-frequency pressure testing system revealed that as salted water temperature increased, the pressure peak of shock wave and relative energy gradually decreased. The above experimental results were mainly due to the effect of salted water temperature on evaporation and condensation rate, which led to different microjet and shock wave behaviors under varying boundary conditions. The study found that as salted water temperature increased (10 ℃ - 40 ℃), the microjet velocity and the maximum pressure peak of the shock wave below the free liquid surface gradually decreased. A novel phenomenon was observed where bubble expansion in high-temperature salted water induced secondary cavitation, forming a "satellite bubble" pattern. These findings provided a new idea to controlling cavitation intensity through temperature in the actual cavitation scene.