Microjet technology can realize tiny droplet spraying, with the prospect of replacing the traditional process, so it has been widely researched and applied. Existing single nozzles have essentially fixed orifice diameters. If different size droplets are to be obtained, this is done by increasing the voltage, stacking multiple droplets to replace the nozzle, and so on. However, by these ways will bring problems such as higher number of satellite droplets, shift of droplet flight, and waste of time. In order to fill the research gap of the current nozzle, a single nozzle with variable nozzle diameter is proposed in this paper. The focus is on the piezoelectric adjustment mechanism that provides thrust for the nozzle deformation. The mechanism can be integrated into a single spray nozzle and can realize the adjustment of the nozzle diameter of a rubber spray nozzle. The piezoelectric adjustment mechanism is mathematically modeled by the elastic beam method, and geometrical parameters are investigated and performance simulation tests are performed by finite element analysis. Finally, the prototype is machined and tested for various properties of the prototype. In addition to this, the prototype was assembled in a single spray nozzle for droplet ejection testing. The experimental results show that the proposed piezoelectric adjustment mechanism is able to deform the rubber nozzle by sufficient thrust to realize rapid adjustment of the nozzle diameter, thus ejecting droplets of different sizes.

中文翻译：

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喷嘴直径调节压电调节机构的设计与实验

微喷射技术可以实现微小的液滴喷涂，具有替代传统工艺的前景，因此得到了广泛的研究和应用。现有的单喷嘴基本上具有固定的孔口直径。如果要获得不同大小的液滴，可以通过增加电压、堆叠多个液滴以更换喷嘴等来实现。但是，这些方式会带来卫星液滴数量多、液滴飞行偏移、浪费时间等问题。为了填补当前喷嘴的研究空白，本文提出了一种具有可变喷嘴直径的单喷嘴。重点是为喷嘴变形提供推力的压电调节机构。该机构可集成在单个喷嘴中，可实现橡胶喷嘴喷嘴直径的调整。采用弹性梁法对压电调节机构进行数学建模，通过有限元分析研究几何参数和性能仿真测试。最后，对原型进行加工并测试原型的各种特性。除此之外，原型还组装在单个喷嘴中，用于液滴喷射测试。实验结果表明，所提出的压电调节机构能够通过足够的推力使橡胶喷嘴变形，实现喷嘴直径的快速调节，从而喷出不同大小的液滴。