High Order Numerical Study of Gas Squeeze Film with Flexural Boundary Condition

Abstract

Ultrasonic levitation system based on Near Field Acoustic Levitation is investigated in this study. A disc is levitated at a height much smaller than the acoustic wavelength where NFAL effect is dominant. A high-order analytical and numerical study on the levitation force induced by gas squeeze film is performed. By taking into account the modal solution on the vibrator whose disunity of the surface displacement can not be ignored, detailed boundary condition of gas squeeze film can achieve a high accuracy in final calculations of time-averaged pressure distribution, load capacity and stiffness of the system. A finite element analysis is compared with analytical solution. By discussing NFAL behavior in gas squeeze films, explanation of essential levitation characters in flexural vibrators is presented, which is important for future study on wafer’s non-contact transportation based on acoustic levitation.