Performance characteristics of gas-lubricated bump-type foil thrust bearing

Abstract

In the present study, the static and dynamic characteristics of Generation II bump-type foil thrust bearings are investigated. For the static characteristics, a 2D compressible Reynolds equation containing effects of centrifugal forces is derived to model the fluid flow in the thin gas film. The compliance of the bearing is calculated using analytical structural stiffness model. The fluid flow equation is coupled to the structural stiffness model and the coupled fluid-structure interaction problem is solved iteratively to obtain the steady-state characteristics of the bearing. For the dynamic characteristics, small perturbations method is used to obtain the linearized equations for the pressure components of dynamic force coefficients. The effects of rotation speed, ramp height, nominal film thickness, friction coefficients at bump foil interfaces, and bump foil stiffness on the static and dynamic characteristics of Generation II foil thrust bearings are thoroughly analyzed.

Unbalance response of micro gas bearing-rotor system considering rarefaction effect

“…19,20 Similarly, the discrete points along the direction can be calculated. Thus, the gas pressure of the bearing is obtained and the load capacity is calculated.…”

Development and application of multiphysics simulation tools for foil thrust bearings operating with carbon dioxide

“…These iteration methods were reviewed and compared by Wang et al [83]. Once steady state performance is achieved, the load capacity F and friction torque T from Reynolds equation are calculated as [84,85], For some applications, the dynamic performance of foil bearings including rotordynamic stiffness and damping coefficients is also of interest. The small perturbation approach has been used to obtain dynamic force coefficients [84].…”

“…However, the current comparison is restricted to laminar formulation shown in Equation 2.4, and the laminar simulation for Eilmer. The load capacity F and friction torque T for the Reynolds equation solution are calculated as [84,85],…”

“…The accuracy of Reynolds equation to model air foil thrust bearings is well established [26,76,84]. This section explores the differences that exist between the two modelling approaches for two operating conditions: solvers, structural deformations are not considered.…”

“…In literature, typically only the ramp and flat regions of foil thrust bearings are considered as the computational domain [8,26,76,84,85], and a fixed static pressure boundary condition is set at the leading and trailing edges (see Figure 5.28(a)). Thus, the groove region between two adjacent bearing pads is neglected, and the pressure in this region is commonly assumed as ambient.…”