泵用压电振子与泵腔体积变化的测试研究

为了准确获得压电泵泵腔体积的变化量,针对影响泵腔体积变化的关键因素——压电振子的变形特性进行分析,并采取非接触的测量方式对基板直径为65 mm,陶瓷直径为60 mm的圆形压电振子进行变形测试.在测试中对该压电振子的中心点在不同电压信号驱动下振幅随频率、驱动电压的变化规律以及压电振子径向各点在正弦电压信号驱动下振幅随半径的变化规律进行了研究.根据压电振子径向各点振幅的变化规律利用Matlab软件进行二次函数曲线拟合计算,得到压电振子的径向切面变形拟合曲线,根据拟合曲线,建立了压电泵泵腔体积变化量的理论计算方法.结果表明：压电振子中心点振幅随频率的增大而逐渐减小,随驱动电压的增大而增大;径向各点振幅随各点半径的增大而减小;拟合计算结果与实测数据基本吻合,最大相对误差仅为6.96%;利用压电泵泵腔体积变化量的理论计算方法,计算得到利用该圆形压电单晶片振子制作的压电泵在100 V,30 Hz正弦电压信号的作用下,泵腔每次振动产生的体积变化量约为34.009 mm3,理论上最大输出流量为61.216 mL/min.

Experimental study of piezoelectric vibrator deformation and cavity volume fluctuation of piezoelectric pump

In order to precisely get the cavity volmne fluctuations of piezoelectric pumps in operation, the deformation characteristic of a circular piezoelectric vibrator, which was one key factor to be re- sponsible for the cavity volume fluctuations, was analyzed and measured in a non-contact manner. The experiment model was a circular piezoelectric unimorph vibrator with substrate and ceramic in the di- ameters 65 mm and 60 mm ,respectively. The relations of amplitude of the center point on the vibrator plane to frequency, driving voltage, and those of amplitude of the points distributed radially in the vi- brator subject to a sinusoidal voltage were studied. Based on quadratic functions, the amplitude of each point on the radius was fitted to get the deformation curve by using a Matlab code. According to the fit- ted curves, a theoretical method for estimating the cavity volume fluctuations was established. The re- suits show that the amplitude of the center point decreases with frequency but increases with driving voltage; the amplitude of each point on the piezoelectric vibrator decreases with radius; the fitted re- sults agree well with the experimental data and the maximum relative error is 6.96% only. According to the theoretical method proposed, it is predicted that under the excitation of sine voltage of 100 V, 30 Hz, the volume fluctuation of pumping cavity is 34. 009 mm3 , and the theoretical maximum output flow rate is 61. 216 mL/min.