压电微喷辅助液滴的多物理场耦合与实验
Multi-Physics Coupling Analysis and Experiments on Piezoelectric Micro-Jet of Auxiliary Droplets

针对微对象辅助释放的操作液滴需求,基于压电驱动的方法进行辅助液滴的分配控制,设计了压电微喷分配器,利用单脉冲压电激励实现非接触式分配,分析了单液滴的形成条件。基于多物理场法,建立压电微喷液滴的多物理场耦合模型,包括压电设备、流固耦合、层流和两相流模型,以此模拟液滴的形成进程,并分析影响液滴形成能力的因素。在构建的微操作系统平台上进行实验分析,结果表明,分配液滴的体积随着驱动电压的幅值和脉冲宽度的增大而增大,较大的参数值利于单液滴形成,与仿真结果分析一致。通过对控制参数的复合调节,所设计的分配器可分配3.5 nL的最小液滴,满足微对象辅助释放的操作液滴要求。直径为200 μm的锡球和聚苯乙烯微球的辅助释放任务的实施,验证了所提出的方法和研制工具的有效性。
To satisfy the manipulation requirement of auxiliary droplets release aiming at micro？？objects, a droplet dispensing method based on piezoelectric drive is presented. The dispenser of piezoelectric micro？？jet, which employs piezoelectric actuator to achieve non？？contact dispensing, is designed. Accordingly, the formation condition of single droplet is analyzed. Subsequently, a multi？？physics coupled model of piezoelectric micro？？jet, including piezoelectric device model, fluid？？solid interaction model, laminar flow model, and two？？phase flow model, is established to simulate the process of droplets formation and analyze the factors affecting the droplet formation capacity. Experimental tests were conducted on a customized micromanipulation platform to verify the performance of the micro？？dispenser. Experimental results indicate that the droplet volume increases with the driving voltage and pulse width. Meanwhile, the single droplet forms more easily with higher driving voltage and larger pulse width, and the results are consistent with simulation. Through the comprehensive adjustment of control parameters, the minimum drop volume of 3.5 nL, which is sufficient for micro？？object auxiliary release, can be obtained using the designed micro？？dispenser. The feasibility of the proposed method and the fabricated micro？？dispenser were verified by the manipulation of tin and polystyrene microspheres with a diameter of 200 μm