Numerical simulation of acoustic field under mechanical stirring*

The present study analyzes the effect of stirring on ultrasonic degradation experiments through acoustic field distribution, which provides a guidance for further improvement of the degradation rate of organic solutions. It is known that in order to eliminate the standing wave field formed by ultrasonic radiation in the water tank, the liquid in the water tank needs to be stirred and the corresponding distribution of acoustic field is simulated by using the finite element method (FEM). The standing wave leads to an uneven distribution of the acoustic field when it is not stirred, and disappears after being stirred, which increases the cavitation area in the ultrasonic cleaning tank. Then, the degradation experiment with agitation is carried out. The experimental results show that the degradation rate of the solution is higher than that when there is no agitation, which confirms the importance of the acoustic field distribution to ultrasonic degradation. In addition, it is clear that with the increase of the stirring speed, the degradation rate increases first and reaches a maximum at 600 rpm before decreasing. Finally, the distribution of flow field is simulated and analyzed.