CAJ | 학술논문

为解决超声雾化换能器用于超低量喷雾时雾化量少、换能器结构复杂等问题，根据超声雾化换能器的工作原理和农药喷施对换能器提出的雾化要求，设计了一种农用超声雾化换能器。首先利用 ANSYS 参数化设计语言建立换能器超声振子的参数化模型；然后对其进行尺寸参数优化，在设定的雾滴体积中径3～5μm范围内，使雾化量达到最大；最后根据优化结果制作样机，进行相关试验测试。试验结果表明，当施加峰-峰值为100 V的交流正弦电压时，超声雾化换能器最大雾化量从1.20提高到1.29 g/min，相比优化前提高了7.5%，93%的雾滴颗粒直径分布在设定的3～5μm范围内，并且实测的换能器谐振频率与仿真结果的误差为5.9%。研究结果为农用超声雾化换能器结构优化设计和雾化量的提高提供参考。
위해결초성무화환능기용우초저량분무시무화량소、환능기결구복잡등문제，근거초성무화환능기적공작원리화농약분시대환능기제출적무화요구，설계료일충농용초성무화환능기。수선이용 ANSYS 삼수화설계어언건립환능기초성진자적삼수화모형；연후대기진행척촌삼수우화，재설정적무적체적중경3～5μm범위내，사무화량체도최대；최후근거우화결과제작양궤，진행상관시험측시。시험결과표명，당시가봉-봉치위100 V적교류정현전압시，초성무화환능기최대무화량종1.20제고도1.29 g/min，상비우화전제고료7.5%，93%적무적과립직경분포재설정적3～5μm범위내，병차실측적환능기해진빈솔여방진결과적오차위5.9%。연구결과위농용초성무화환능기결구우화설계화무화량적제고제공삼고。
In order to solve the problems when ultrasonic atomization transducer was used for ultra-low-volume spraying pesticides, i.e. the atomization flow was little and the transducer’s structure was complex, this paper presented a new structure of agricultural ultrasonic atomization transducer based on the atomization requirements proposed by the working principle of ultrasonic atomization transducer and agricultural pesticide spraying. The transducer mainly consisted of a venturi tube, a cylindrical square-cavity, an ultrasonic vibrator, a rubber washer and a flange cover. When the high-frequency alternating current (AC) voltage was applied on the ultrasonic vibrator, liquid was atomized. In the meantime, the circumscribed air pump formed the air vortex in the square-cavity, which would drive the droplet to rotate and move upward, prevent the spread of droplet and avoid attaching on the inner wall of the vessel. Firstly, the parametric model of the ultrasonic vibrator was established and then optimized with ANSYS parametric design language (APDL) to control the droplet diameter of the transducer within the setting range and maximize the atomization flow. In the atomization process, we chose the electrode diameter and the thickness of the ultrasonic vibrator as the design variables, the vibration amplitude of the ultrasonic vibrator as the objective function, and the driving frequency as the constraint condition. Secondly, penalty function was used to solve the optimization problem with inequality constraints. Meanwhile, the modal assurance criteria (MAC) were adopted to recognize the target modals intelligently by ANSYS finite element software. If the value of MAC was closed to 1, the target model was similar to the reference model. This indicated that the vibration along the axial direction was concentrated on the surface of the ultrasonic vibrator and the vibration amplitude was larger than other models. Thirdly, a prototype built based on the optimization results was manufactured to conduct the atomization flow measurement experiment and the droplet diameter measurement experiment. The measured resonant frequency of the optimized transducer was 1.53 MHz, which was very close to the simulated value of ANSYS finite element software (1.62 MHz) and the error was 5.9%. The measured resonant frequencies of the transducer before and after optimization were 1.56 and 1.53 MHz respectively. When the excitation frequency was at the resonant frequency 1.53 MHz, the atomization flow rate of the optimized agricultural ultrasonic atomization transducer reached the maximum. If the excitation frequency of the ultrasonic atomization transducer was lower or higher than the resonant frequency, the atomization flow rate would be reduced, which illustrated that the ultrasonic vibrator should work in the resonant frequency to make the transducer produce the largest amount of aerial fog. The maximal atomization flow rate of the agricultural ultrasonic atomization transducer increased from 1.20 to 1.29 g/min when applying an AC sine-wave voltage whose peak-peak value was 100 V, that was, it was raised by 7.5% compared with the flow before optimization. At the same time, the VMD (volume median diameter) of droplet measured by a laser particle size analyzer (Winner318B) was consistent with the design requirement. Research results provide a scientific reference for optimum structural design of agricultural ultrasonic atomization transducer and the increase of the atomization flow.