Simulation of the formation and characteristics of ultrasonic fountain

•The shape of the ultrasonic fountain is numerically simulated.•The surface tension and the radiation pressure are taken into account in simulation.•The influence of input pressure and species of solution on the shape of the ultrasonic fountain is discussed.•The difference between the ultrasonic and the pump fountain are found.

In order to design an ultrasonic apparatus with a high throughput rate for generating atomization, the mechanism of fountain characteristics is important because the throughput rate of the ultrasonic atomization is decided by the area of the fountain surface. The formation of the fountain can be numerically studied by taking into account the effect of surface tension and radiation pressure. We have investigated the shape of the fountain with different ultrasound parameters or different kinds of solutions. When the amplitude of input sound pressure is higher than 1.3 × 105 Pa, the liquid separates from the ultrasonic fountain after irradiation for a very short period. It is further found that the area of the fountain surface increases with the concentration of the ethanol due to its low surface tension, density and sound speed. Finally, we discuss the difference between the ultrasonic fountain and the pump fountain, and find that the velocity field in the reactor induced by the pump is higher than that by the ultrasound.