Characterization of static air foil thrust bearing performance: an elasto-gasdynamic analysis for aligned, distorted and misaligned operating conditions

Lehn, Andreas; Mahner, Marcel; Schweizer, Bernhard

doi:10.1007/s00419-017-1337-7

Cited by 14 publications

(5 citation statements)

References 29 publications

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“…Different from magnetic bearing, foil gas bearing is a kind of dynamic pressure fluid lubrication bearing [ 18 ]. For foil gas bearing, the foil can give the bearing elastic support, which promotes the realization of the wedge effect between the rotor and the bearing.…”

Section: Methodsmentioning

confidence: 99%

Performance for rotor system of hybrid electromagnetic bearing and elastic foil gas bearing with dynamic characteristics analysis under deep learning

Sun

2021

PLoS ONE

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The bearing-rotor system is prone to faults during operation, so it is necessary to analyze the dynamic characteristics of the bearing-rotor system to discuss the optimal structure of the convolutional neural network (CNN) in system fault detection and classification. The turbo expander is undertaken as the research object. Firstly, the hybrid magnetic bearing-rotor system is modeled into the form of four stiffness coefficients and four damping coefficients, so as to analyze and explain the dynamic characteristics of the system. Secondly, the ambient pressure is introduced to analyze the dynamic characteristics of the elastic foil gas bearing-rotor system based on the changes in the dynamic stiffness and dynamic damping of the gas bearing. Finally, the CNN is introduced to be applied in the detection of faults of bearing-rotor system through determining the parameters of the constructed CNN. The results show that the displacement of the rotor increases and the stiffness decreases with the acceleration of the speed of the electromagnetic bearing. The maximum displacement of the rotor can reach 135μm, and the maximum stiffness can be reduced to 35×105N/m. Increase of ambient pressure causes enhancement of main stiffness of the gas bearing, and the main damping decreases accordingly. Analysis of the classification accuracy and loss function based on the CNN model shows that the convolution kernel size of 7*1 and the batch size of 128 can realize the best performance of CNN in fault classification. This provides a data support and reference for studying the dynamic characteristics of the bearing-rotor system and for the optimization of CNN structure in fault classification and detection.

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Section: Methodsmentioning

confidence: 99%

Performance for rotor system of hybrid electromagnetic bearing and elastic foil gas bearing with dynamic characteristics analysis under deep learning

Sun

2021

PLoS ONE

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“…The study found that there exists an optimum incline (ramp) height of the foil structure to achieve the maximum load capacity. Lehn et al [19,20] presented a thermo-elasto-hydrodynamic model for GFTBs. They used shell theory to model the structures of the top and bump foils and calculated the hydrodynamic pressure and temperature by solving the Reynolds equation and the three-dimensional (3D) energy equation, respectively.…”

Section: Introductionmentioning

confidence: 99%

Static Performance Measurements and Model Predictions of Gas Foil Thrust Bearing with Curved Incline Geometry

Hwang,

Mehdi,

Kim

2023

Lubricants

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Gas foil thrust bearings (GFTBs) have been successfully used to support the axial load of oil-free microturbomachinery with low drag friction due to the low viscosity of gas or air used as a bearing lubricant. However, the widespread use of GFTBs in various high-power turbomachinery still needs reliable test data and an accurate predictive model. This research measures the height profile of a test GFTB to determine its actual incline geometry and estimate the drag torque of the GFTB. The measured GFTB height profile demonstrates that the incline geometry is closer to a quadratic curve than a line, which has been conventionally used to model GFTBs mathematically. The newly developed GFTB test rig is used to measure the lift-off speed, drag torque, and maximum load capacity of the test GFTB. A series of rotor speed-up tests estimate that the lift-off speeds of the GFTB increase with the increase in preloads. The maximum load capacity is determined by increasing the static load on the GFTB until a sudden sharp peak in the drag torque appears. The new GFTB model using quadratic incline geometry is in suitable agreement with the measured height profile of the GFTB incline and measured drag torque during the load capacity test. In addition, a comparison of the predicted GFTB performances reveals that the quadratic incline geometry model predicts a higher load capacity than the linear model.

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“…and under forced excitation, the forced response dominated the deformation of the bearing. Lehn A et al [37] found the capacity of the GFJB is superior to rigid thrust bearings. The overall compliance of the pads in a GFJB had resulted in the superior behavior of the GFJB to rigid thrust bearings.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Unsteady Characteristics of Gas Foil Journal Bearings with Fluid–Structure Interaction

et al. 2023

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Gas foil journal bearings (GFJBs) have been widely employed in high-speed rotating machinery in the aviation industry. However, the role of fluid–structure interaction in the unsteady aerodynamic character of the gas film and the dynamic response of the elastic foils have not yet been clarified. In this study, an unsteady shearing flow interacting with an exciting deformation of the top or bump foils was investigated by means of a large eddy simulation with bidirectional fluid–structure interaction (BFSI). The result shows that the main frequencies and amplitudes of stable fluctuations of different flow field parameters at different positions are different. The oscillating duration in the solid domain is much less than that in the fluid domain. The main positions for the interaction between the gas film pressure and the elastic foil are on both sides of θ = π. Compared with the case without FSI, the presence of the elastic foil flattens the distribution of the pressure of the gas film. As the rotational speed increases, the main frequency and the amplitude of pressure in the fluid domain continuously increase. With FSI, there is no interference frequency near the main frequency, which improves the stability of the shearing flow. However, an interference frequency appears near the main frequency of total displacement in the solid domain. The analysis in this paper lays the foundation for unsteady fluid–structure interaction research.

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Characterization of static air foil thrust bearing performance: an elasto-gasdynamic analysis for aligned, distorted and misaligned operating conditions

Cited by 14 publications

References 29 publications

Performance for rotor system of hybrid electromagnetic bearing and elastic foil gas bearing with dynamic characteristics analysis under deep learning

Performance for rotor system of hybrid electromagnetic bearing and elastic foil gas bearing with dynamic characteristics analysis under deep learning

Static Performance Measurements and Model Predictions of Gas Foil Thrust Bearing with Curved Incline Geometry

Numerical Investigation of Unsteady Characteristics of Gas Foil Journal Bearings with Fluid–Structure Interaction

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