Static, Dynamic, and Thermal Properties of Compressible Fluid Film Journal Bearings

Abstract

Modern turbo-machinery applications, high-speed machine tools, and laboratory equipment require ever-growing rotational speeds and high degree of precision and reliability. Gas journal bearings are often employed because they meet the demands of high-speed performance, in a clean environment, and work great efficiency. A great deal of literature has concentrated on the analysis and prediction of the static and dynamic performance of gas bearings, assuming isothermal conditions. The present contribution presents a detailed mathematical modeling for nonisothermal lubrication of a compressible fluid film journal bearing, in order to identify when this type of analysis should be of concern. Load capacity, stiffness, and damping coefficients are determined by the solution of the standard Reynolds equation coupled to the energy equation. Numerical investigations show how bearing geometry, rotational speed and load influence the bearing performance. Comparisons between isothermal and thermohydrodynamic models and discrepancies are quantified for three different types of bearing geometries.

KEY WORDS:

• Fluid Film Bearings
• Compressible Reynolds Equation
• Thermohydrodynamic Lubrication

Acknowledgments

Review led by Gregory Kostrzewsky