Numerical Analysis of a Horizontal Flexible Rotor Supported by a Squeeze Film Air Bearing Based on Near-Field Acoustic Levitation

Abstract

Acoustic levitation is a method through which an object is suspended at a stable position against gravity by means of an acoustic radiation force produced by intense sound waves. This technique encompasses two different approaches: standing wave acoustic levitation and near-field acoustic levitation. Over the last few decades, the application of near-field acoustic levitation in the development of squeeze film bearings has been investigated by a number of researchers. In most works, the bearings were experimentally tested on a vertical test rig that could be tilted to control the radial load applied to the bearings. Besides, the dynamic modeling of the rotor-bearing systems was performed by considering the rotor as a rigid body. In this context, the present work proposes to develop a finite element model to investigate the dynamic behavior of a horizontal flexible rotor supported by two bearings, one of them being a squeeze film air bearing based on near-field acoustic levitation. The numerical results demonstrate that due to its limited load capacity, low damping, and small radial clearance, this type of bearing is recommended for use in light rotating machines with low unbalance level.