The acoustic levitation and simultaneous contactless transportation of matter in the third resonance mode (H3‐mode) of a line‐focused system.

Abstract

We investigate theoretically herein higher modes of resonance for transportation of matter (particles or droplets) in line‐focused acoustic levitation. Contactless transportation was achieved by varying the height between the radiating plate and the reflector. Transportation and levitation of volatile liquids, in particular, involves two limits of the acoustic forces. The lower limit corresponds to the minimum force required to levitate a droplet, i.e., to overcome the gravitational force. The higher limit corresponds to the maximum acoustic pressure before atomization of the droplet occurs. By increasing the size of the droplet, the lower limit increases and the higher limit decreases. Therefore, in order to have large droplets levitated in the device, a relatively flat radiation pressure over the translation distance is needed. In this study, using a finite element model, the Gor’kov potential was calculated for different heights between the reflector and the radiating plate. It was found that the best levitation configuration is the H3‐mode, which represents a good compromise between high levitation power and smooth pattern transition. The H3‐mode also allows three translation lines in parallel.