Experimental investigation of surface acoustic wave atomization

Surface acoustic wave (SAW) atomization is a promising and relatively new method in the atomization field. However, the exact process is obscure due to the difficulty of observing such a small-scale series of complicated hydrodynamic processes. Lacking enough observations also makes it difficult in predicting the atomized droplet size distribution. Therefore, this study employed fundamental experimental methods to investigate the mechanism for SAW atomization. Firstly, a 20 MHz SAW device was fabricated by UV photolithography technology. The whole atomization process was then recorded by using a high-speed camera and classified each reaction stage according to the applied power. The experiment reveals three main peaks in the size distribution and corresponding mechanisms are employed to provide a detailed explanation for each. Experimental results also show that Eckart streaming and Schlichting streaming dominate different stages in generating different scale droplets. Two methods of predicting the mean diameter of atomized droplets are compared in this work.