Numerical simulation of three physical fields in counter‐current ultrasound

Abstract Power ultrasound is a kind of green and environmentally friendly processing technology. Still, because of its uneven distribution of acoustic pressure in the propagation medium, the large‐scale industrial application of ultrasound is limited. In order to make more effective use of ultrasound waves, this paper uses a counter‐current ultrasound‐assisted extraction container as the geometric model of simulation, calculates the distribution of the acoustic pressure field in the container by COMSOL Multiphysics software, and investigates the effect of acoustic pressure on the fluid field, and temperature field. The simulation results showed that the acoustic pressure increased with the increase of ultrasound power and frequency, tended to balance with the rise of propagation distance, and the cavitation effect was more likely to occur. The propagation of ultrasound in the fluid medium increased the velocity and vorticity of the fluid, which was conducive to the generation of mixing effects. Under the ultrasound pulse working mode for 4 min, the fluid temperature on the central axis increased in a stepped order, with a maximum increase of 19.3°C. We can see that the establishment of the simulation model provides some theoretical guidance for the more practical application of ultrasound in the food industry. Practical Applications The limitation of ultrasound application mainly lies in the nonuniform distribution of acoustic pressure when ultrasound propagates in the fluid medium. Therefore, mastering the distribution of multiple physical fields in the reaction zone through simulation has important technical support and theoretical guiding significance for designing efficient ultrasound‐assisted extraction equipment and large‐scale industrial production of ultrasound.