CAJ | 학술논문

针对现有基于郎之万夹心振子的低频超声雾化喷头驱动电压高、工作效率低、电路和喷头发热严重、体积较大难以生成超细雾滴等缺点，研发了一种低频弯振超声雾化喷头，该喷头的核心工作部件是轴对称复合弯振压电振子。为了研究轴对称复合弯振压电振子关键结构参数对其基频的影响，在 ANSYS 平台上，建立了轴对称复合弯振压电振子的虚拟试验系统。采用正交试验设计方法，对试验结果进行了极差分析和回归分析，建立了试验指标轴对称复合弯振压电振子基频与压电陶瓷的外径、内径、厚度及金属圆片直径的回归数学模型。极差分析和回归分析结果表明：压电陶瓷的外径、内径及金属圆片直径对轴对称复合弯振压电振子基频的影响极显著；压电陶瓷厚度对轴对称复合弯振压电振子基频的影响显著；各影响因素对低频弯振超声雾化喷头基频的影响主次顺序依次为压电陶瓷外径、压电陶瓷内径、金属圆片直径、压电陶瓷厚度。轴对称复合弯振压电振子物理样机的基频测试试验结果和回归数学模型预测结果对比表明该回归模型的预测误差基本在5%以内，从而验证了回归模型预测的精准性。该回归模型为轴对称复合弯振压电振子结构参数的优化设计提供了较为实用的数学模型。
침대현유기우랑지만협심진자적저빈초성무화분두구동전압고、공작효솔저、전로화분두발열엄중、체적교대난이생성초세무적등결점，연발료일충저빈만진초성무화분두，해분두적핵심공작부건시축대칭복합만진압전진자。위료연구축대칭복합만진압전진자관건결구삼수대기기빈적영향，재 ANSYS 평태상，건립료축대칭복합만진압전진자적허의시험계통。채용정교시험설계방법，대시험결과진행료겁차분석화회귀분석，건립료시험지표축대칭복합만진압전진자기빈여압전도자적외경、내경、후도급금속원편직경적회귀수학모형。겁차분석화회귀분석결과표명：압전도자적외경、내경급금속원편직경대축대칭복합만진압전진자기빈적영향겁현저；압전도자후도대축대칭복합만진압전진자기빈적영향현저；각영향인소대저빈만진초성무화분두기빈적영향주차순서의차위압전도자외경、압전도자내경、금속원편직경、압전도자후도。축대칭복합만진압전진자물리양궤적기빈측시시험결과화회귀수학모형예측결과대비표명해회귀모형적예측오차기본재5%이내，종이험증료회귀모형예측적정준성。해회귀모형위축대칭복합만진압전진자결구삼수적우화설계제공료교위실용적수학모형。
Ultrasonic atomization had been paid so much attention as a new spraying technique recently. With such advantages as small droplets, uniform size distribution, high roundness, large atomization quantity and low liquid delivery pressure, ultrasonic atomization is widely used in aeroponic, agricultural humidifying fields, reagents atomization treatment, semiconductor etching and so on. According to different the working frequency, the current ultrasonic atomizer mainly includes high-frequency (working frequency is greater than 1 MHz) and low-frequency (working frequency is in the range between 20 kHz and 100 kHz). Application of high-frequency ultrasonic atomizer was highly limited for such disadvantages as low reliability, high driving voltage, short continuous working time, high energy consuming, failing in atomizing high viscosity liquids, small and unstable atomization amount. Above all, chemical structures of liquids atomized by high frequency ultrasonic atomizer would be changed, so this kind of atomizer was just suitable for atomizing water. Current actuators of low-frequency ultrasonic nozzles were mainly made of Langevin piezoelectric actuators, which included piezoelectric discs, front covers and rear covers. Such disadvantages as high driving working voltage, low efficiency, severe heat, large volume and uneven distribution of droplets limited this kind of low-frequency ultrasonic nozzles to be spread. In order to develop a low frequency ultrasonic nozzle with such advantages as low driving working voltage, high working efficiency, small feat, fine and uneven distribution of droplets, a novel low frequency ultrasonic nozzle, whose actuator was an axial symmetry bending composite piezoelectric actuator, was proposed and designed in this paper. While the core component of this ultrasonic nozzle, namely, an axial symmetry bending composite piezoelectric actuator was composed of a piezoelectric ceramic ring and a metal disc. At the present, the fundamental vibration frequency of this kind of actuator was mainly applying Rayleigh-Ritz theory based on the minimal energy principle to search an approximate value without considering electronic-mechanical coupling. Because Rayleigh-Ritz theory ignored the effect of t electronic-mechanical, the calculation result error was too bigger. At the same time, this method was so complicated that it’s not suitable for engineering calculation. So it’s necessary to find a simple calculation formulation for engineering application. In order to find out how key structural parameters of axial symmetry bending composite piezoelectric actuators influence on their fundamental frequencies, a virtual testing system based on finite element method was established. In this virtual testing system, element Solid 98, an tetrahedral coupled-field solid element in ANSYS software was used to mesh the prototype of axial symmetry bending composite piezoelectric actuator. Combined with an orthogonal experimental design method, an orthogonal protocol of four factors and five levels was proposed. Based on virtual test data, a regression model between fundamental frequency and key structural parameters of piezoelectric vibrators (significance levelα=0.05) was established. The regression model indicated that: i)P-valuesof outer diameters, inner diameters of nozzle’s piezoelectric discs and diameters of metal discs were 1.2×10-8、9.97×10-6、2.093×10-3respectively. It indicated that fundamental frequencies of axial symmetry bending composite piezoelectric actuator were affected by outer diameters, inner diameters of nozzle’s piezoelectric discs and diameters of metal discs highly significantly; ii)P-valueof piezoelectric disc thickness was 0.012813. It indicated that fundamental frequencies were influenced by piezoelectric disc thickness significantly; iii) outer diameter, inner diameter, thickness of nozzle’s piezoelectric ceramic and diameter of metal disc influence frequencies of those actuators in turn. Tests of the nozzle’s acoustic impedance were conducted too by PV 70A, an instrument used for measuring piezoelectric part’s acoustic impedance parameters. Compared fitting results with test results, fitting errors are nearly all less than 5%, so the regression model was verified. This regression model made it easier to optimize axial symmetry bending composite piezoelectric actuator design.