Modelling of Compliant-type Gas Bearings: A Numerical Recipe

Sebastian von Osmanski, Jon S. Larsen, Ilmar Santos*

*Corresponding author for this work

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Abstract

Despite its merits, the Gas Foil Bearing (GFB) suffers from several inherent limitations which could likely be overcome using active radial injection. This hence represents a natural next step, even though several issues relating to the foil structure modelling remain unresolved. A prerequisite for the development of any model-based feedback control scheme is a model capturing the effects of gas injection on the system dynamics. The currently presented work on a generic numerical recipe for GFB simulation is intended as a step towards such a model.
The aim of the present work is to consolidate the existing state of the art knowledge on GFB modelling into a generic framework that can act as an efficient platform for further research. By creating a structure where the same pieces of code can be applied for simulation of a wide range of rotors supported by any number of rigid or compliant type gas bearings — with or without injection — the available experimental results can be utilized optimally for validation. Furthermore, the programming intensive optimizations necessary to obtain tolerable solution times can be more easily reused.
The framework consists of three domains treating the rotor, the foil structure and the fluid film respectively, along with clear-cut domain interfaces based on linear mappings. In the fluid domain, the film is modelled using the Modified Reynolds Equation dizcretised using finite volume, leaving the injection flow to an auxiliary model. Both the rotor and the compliant structure are represented in generic state-space formats facilitating various different models for both domains. The global system is solved both statically and in time using efficient general purpose routines exploiting e.g. analytical Jacobian matrices and sparse direct linear solvers.
Original languageEnglish
Title of host publicationProceedings of 13th SIRM: The 13th International Conference on Dynamics of Rotating Machinery
Place of PublicationKgs. Lyngby
PublisherTechnical University of Denmark
Publication date2019
Pages14-27
ISBN (Electronic)978-87-7475-568-5
Publication statusPublished - 2019
Event13th International Conference on Dynamics of Rotating Machinery - Technical University of Denmark, Copenhagen, Denmark
Duration: 13 Feb 201915 Feb 2019
Conference number: 13

Conference

Conference13th International Conference on Dynamics of Rotating Machinery
Number13
LocationTechnical University of Denmark
CountryDenmark
CityCopenhagen
Period13/02/201915/02/2019

Cite this

von Osmanski, S., Larsen, J. S., & Santos, I. (2019). Modelling of Compliant-type Gas Bearings: A Numerical Recipe. In Proceedings of 13th SIRM: The 13th International Conference on Dynamics of Rotating Machinery (pp. 14-27). Kgs. Lyngby: Technical University of Denmark.