Study on dynamic characteristics of acoustic levitation

The dynamic characteristics of acoustic levitation were investigated for the purpose of containerless processing of materials. Experimental measurements were accomplished on the variations of sound pressure level with both axial position z(6. 5mm≤z≤ 27. 5mm) and radial position r(1mm≤r≤16mm) in a cylindrical resonant tube(∅34mm × 45mm) of a single axis acoustic levitator. The results showed that the minimum sound pressure levels in both axial and radial directions occur at the centres of two transverse intercepting planes with z=8. 5mm and z=21. 5mm, which were identified as the sound pressure nodes not only of the axial direction but also of the radial direction, and hence were expected to have good levitation stability. This was further proved by experimental observations.