Flow and sound field analysis of agricultural ultrasonic atomizing nozzle

To solve the problem of large size of fog droplets generated in plant protection, which are not conducive to
absorption by target plants and result in pollution due to excessive application, an ultrasonic atomizing nozzle suitable for
agricultural plant protection was designed. First, a geometric model of the agricultural ultrasonic atomizing nozzle was
established using the Design Modeler module in ANSYS FLUENT. The FLUENT simulation software program was then
employed to simulate the internal flow field of the nozzle, and the internal flow field cloud image and sound pressure for
various cavity depths and cavity diameters were investigated. Finally, the vapor holdup of the flow field inside the nozzle
were simulated. The results indicate that the internal cavity depth and diameter of the agricultural ultrasonic atomizing nozzle
affect the generation of a cavitation vortex inside the nozzle and the magnitude of the sound pressure. As the cavity depth and
diameter are increased, the amplitude of sound pressure first increases and then gradually decreases. The cavity diameter has a
stronger influence on the amplitude of sound pressure than the cavity depth does. The sound pressure amplitude changes
marginally with the cavity depth. Simulation revealed that the ultrasonic intensity is highest and the corresponding
atomization effect is strongest when the depth and diameter of the of the resonant cavity are 4 and 3 mm, respectively. When
the inlet pressure is 2MPa, the percentage of the flow field of the ultrasonic atomizing nozzle with vapor content higher than
80% is approximately 33.94% higher than that achieved before parameter optimization. The effective space utilization rate
inside the nozzle is improved.