## 5 Results and Discussion  
Figure 10 shows the frequency sweep curves of the vibration velocity and amplitude, vibration modes of resonance points, deformation diagram of the piezoelectric oscillator and atomization rates at the resonance points. In this experiment, the flared end of the atomizer is attached to the water tank and is placed in contact with the fluid surface (i.e., in the forward direction). In this experiment, no visible atomization was observed below a resonant frequency of 15.9 kHz. As shown in Figure 10, the atomization rate increased gradually with resonance frequency and at the resonance frequency of 121.1 kHz, the atomization rate was maximized (2.805 mL/min). However, at the resonance frequency of 148.3 kHz, the atomization rate decreased significantly. When the frequency increases (where 1 refers to the increasing frequency trend), the dispenser deformation becomes more complex, which indicates that its rate of deformation curvature change and the rate of tapered aperture volume change both increase. Furthermore, the rate of liquid chamber volume change decreases (where 2 refers to the decreasing rate of liquid chamber volume change trend). However, the atomization rates at the resonant frequencies generally increase incrementally. This finding contradicts the findings of previous discussions on the pumping effect caused by volume changes and the atomization generated under ultrasound conditions. No clear explanations are given in the literature [29; 38; 39]. When the rate of dispenser deformation curvature change increases (referring to larger changes in the dynamic cone angle) as shown in Figure 3, the dynamic cone angle pumping effect becomes stronger, and this results in an increase in the atomization rate. Therefore, the vibration and the elastic deformation of the dispenser allow the micro-dynamic cone angle to act as a pump. There are two possible reasons for the reduction of the atomization rate at the sixth-order resonance point. The first is that the overall displacement amplitude decreases at higher resonance modes and the rate of change also decreases. The second reason is that the flow velocity in the aperture increases with increasing frequency, and this leads to the increased flow resistance. Therefore, the dynamic cone angle plays an important role in the atomization. Figures 11 and 12 show that the atomization rate and atomization height measured in the forward direction are much higher than those measured in the reverse direction. This atomization rate and atomization height difference increases as the working voltage increases. As determined through the analysis above, the atomization of the vibrating mesh atomizer is caused by pressure atomization and dynamic cone angle atomization. The pressure atomization is caused by the change of the volume in the liquid chamber, and the dynamic cone angle atomization is caused by the change of the volume in the micro-cone hole. When the vibrating mesh atomizer is working in the forward configuration, the atomization rate is the sum of the pressure atomization and the dynamic cone angle atomization, as shown in Equation (8). Therefore, the atomization rate in the forward direction is much higher than in the reverse direction. The initial velocity of the atomized droplets is more rapid at the exit of the micro-cone hole when the atomization rate is larger. Therefore, the atomization height in the forward direction is much higher than in the reverse direction. The experiment shows that the micro-cone hole is integral to and influences the atomization behavior. Figure 9: A photograph of how the aperture is measured. Figures 11 and 12 show that at the same resonance frequency, with increasing driving voltage, the atomization rate and the atomization height gradually increase. When the driving frequency is unchanged, the vibration mode of the piezoelectric vibrator is also unchanged. With increasing driving voltage of the piezoelectric vibrator, the deformation of the piezoelectric vibrator amplitude is greater. [PERSON] et al.