多压电膜式零质量射流激励器的设计与性能研究

The design and performance study of a multi-diaphragm piezoelectric synthetic jet actuator

设计了一种多压电膜式零质量射流激励器,并利用热线风速仪,得到了对应于射流中心线上固定位置处速度最大时的最佳频率.在该频率下,测量了零质量射流在不同孔径时沿中心线的速度分布;测量、分析和比较了不同激励膜数目对射流出口速度分布的影响.表明:在其他条件完全相同的情况下,一片振动膜时的激励器出口中心线上的平均速度和峰值速度,都较5片膜的情况小一半左右,而3片和5片压电膜时的激励器性能差别却不大.也就是说,虽然压电膜的数目增加能使激励器出口射流的能量增加,但这两者之间并非呈线性关系.此外还用PIV测量方法,直观地显示了射流出口的涡结构.

Considering the shortcomings and incompetence of conventional piezoelectric synthetic jet actuator （PE-SJA）, a novel multi-diaphragm PE-SJA design was proposed in this paper and some detailed experimental studies were carried out upon it. By using the hotwire anemometry, the optimum resonance frequency of the actuator was obtained through measuring the velocity magnitude at a fixed position on the axis of the orifice exit flowfield at different frequencies. Then the orifice exit velocities with different numbers of diaphragm were measured, analyzed and compared, which showed that at the axis of the orifice exit flowfield the averaged and peak velocities of one-diaphragm PE SJA was only the half of those of the five-diaphragm PE-SJA. But the performance of three-diaphragm PE-SJA was almost the same as that of the five-diaphragm PE-SJA, which suggested that although the performance of the PE-SJA increase with the number of the piezoelectric diaphragm, it did not occur in a linear way. PIV was also used to obtain the structure of vortex of the flowfield.