A Thermohydrodynamic Analysis of Foil Journal Bearings

Abstract

A thermohydrodynamic model is developed for predicting the three-dimensional (3D) temperature field in an air-lubricated, compliant foil journal bearing. The model accounts for the compressibility and the viscosity-temperature characteristic of air and the compliance of the bearing surface. The results of numerical solutions are compared to published experimental measurements and reasonable agreement has been attained. Parametric studies covering a fairly wide range of operating speeds and load conditions were carried out to illustrate the usefulness of the model in terms of predicting the thermal performance of foil journal bearings.

Analysis of the bearing nodes loads of turbine engine at an unmanned helicopter during a jump up and jump down maneuver

“…Properties of gas bearings including a foil gas bearings are described in several studies based on the experimental works [7,8,12]. There are many mathematical models and studies describing the operation of the bearings, including the thermal-hydrodynamic analysis like [14], where the established mathematical models can be used to design more advanced foil bearings, in particular foil bearings with variable axial stiffness. Interest of gas bearing is very high, but it should be remembered that the bearing assembly design process requires knowledge of the applications of your device and especially the knowledge of the dynamic conditions during the operation.…”

Studies on thermal effects in aerodynamic foil journal bearings

“…The Couette Approximation used in their analysis provided a reasonable tool for the temperature approximation. Peng and Khonsari, (2006) considered the effect of temperature field on the dynamical characteristic in bump foil air bearings based on their previous study (Peng and Khonsari, 2004). A simultaneous solution to the Reynolds equation and the energy equation with the appropriate boundary conditions was attained.…”

“…As a result, the load capacity suffers, the stiffness decreases, and the damping mechanism can be changed under the combination of temperature effect and load condition (Peng and Khonsari, 2006). One major concern is the localized overheating of the foil material due to nonuniform viscous heating within the gas film when the bearing operates at high speed and/or high load conditions.…”

A New Analysis Tool Assessment for Rotordynamic Modeling of Gas Foil Bearings

“…In (Ref. 20), the authors extend their model to include the energy equation and therefore, can predict the temperature field in the gas film. While the model includes calculation of the temperature field, it does not include the thermal deformations of the foil structure, which is believed to detract significantly from the load capacity of gas foil bearings.…”

“…19) and thermohydrodynamic (Ref. 20) analyses of gas foil journal bearings. In the isothermal model, the authors use a model similar to Heshmat's (Refs.…”