Gas-dynamic foil bearing model

Temis, Yu. M.; Temis, M.Yu.; Meshcheryakov, A. B.

doi:10.3103/s1068366611030111

Cited by 13 publications

(5 citation statements)

References 6 publications

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“…22 Many authors have presented AFB models with a structural model of the top foil. [23][24][25][26][27][28][29] These models have been used to investigate the influence of the top foil on the AFB performance. The most common studies are on the effects of top foil sagging, i.e.…”

Section: Introductionmentioning

confidence: 99%

Transient and steady state behaviour of elasto–aerodynamic air foil bearings, considering bump foil compliance and top foil inertia and flexibility: A numerical investigation

Nielsen

Santos

2017

Proceedings of the Institution of Mechanical Engineers, Part J:

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This work gives a theoretical contribution to the problem of modelling air foil bearings considering large sagging effects in the calculation of the non-linear transient and steady state response of a rigid rotor. This paper consists of two parts: the development of a miltiphysics model of the air foil bearing, and a numerical parameter study of a rigid journal supported in an air foil bearing with a partially supported top foil. The mathematical model of the air foil bearing is centred around the finite element models of both the air film and the top foil structure. These finite element models utilise two types of eight-node isoparametric elements. The rotor is modelled as a rigid body without rotational inertia, i.e. as a journal. The bump foil is included via a bilinear version of the simple elastic foundation model. This paper introduces the bilinear simple elastic foundation model, which combined with the top foil structure model, enables a separation of the top foil and the bump foil. A phenomenon associated within areas of the top foil is where the aerodynamic pressure is sub-ambient. The parameter study investigates the performance of three air foil bearings with partially supported top foils and one air foil bearing with a fully supported top foil. The steady state responses of a journal supported by these air foil bearings are investigated for varied rotational speeds and journal unbalances as well as the top foil sagging in the unsupported area. The study reveals that sub-harmonic vibrations associated with a large journal unbalance can be eliminated by a proper design layout of the bump foil, i.e. placement of the unsupported area. The positive effect is attributed to ‘equivalent shallow pockets’ formed by the sagging top foil.

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Section: Introductionmentioning

confidence: 99%

Transient and steady state behaviour of elasto–aerodynamic air foil bearings, considering bump foil compliance and top foil inertia and flexibility: A numerical investigation

Nielsen

Santos

2017

Proceedings of the Institution of Mechanical Engineers, Part J:

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“…These software tools are: LS-DYNA, ABAQUS, STAR-CD, ANSYS modules -CFX and Fluent, Flow Vision and others [5].…”

Section: Modeling Proceduresmentioning

confidence: 99%

Numerical computation of the main gas-dynamic bearing static characteristics for the ball gyroscope

Ignatovskaya

Golikov

2016

MATEC Web of Conferences

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Abstract. The numerical computation questions and analysis of the engineering calculation of the main gas-dynamic bearing static characteristics for the ball gyroscope experimental model are considered. The developed gyroscopic device construction is provided. These investigations for evaluation of the possibility to realize a sensitive element, which base on the developed device were provided. It is supposed, that this sensitive element can be used in information measuring systems of various applications. The main calculation data, such as load-bearing capacity and other characteristics of the hemispherical gas-dynamic bearing is carried out. According to the attained results, preliminary implications are stated. The basic problems for the further research are determined.

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“…Coulomb friction was taken into account by using bookkeeping algorithms for the different stickslip states of the contacts [16,17], or by using penalty [18,20]o r Lagrange multipliers algorithms [19]. The next natural step was the use of nonlinear elasticity commercial codes for modeling the foils [21][22][23][24]. The results presented in Ref.…”

Section: Introductionmentioning

confidence: 99%

A New Structural Bump Foil Model With Application From Start-Up to Full Operating Conditions

Arghir

Benchekroun

2019

Journal of Engineering for Gas Turbines and Power

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This paper presents a new structural bump foil model that can handle all operating conditions from start-up to full speed. The model is based on a nonlinear contact algorithm with friction and gaps. The top foil is modeled as a curved beam while bump foil uses a coupled truss model. The model considers the gaps between the bump foil and the bearing casing, between the bump foil and the top foil and between the rotor and the top foil. Thus, any numerical interference between the rotor and the top foil is avoided. A mixed lubrication model is used for the thin film pressures. Following this algorithm, contact pressures appear if the film thickness is less than three times the equivalent roughness of the rotor and of the top foil. Fluid pressures are calculated from numerical solutions of Reynolds equation while contact pressures, if present, are calculated with the model of Greenwood and Williamson. The model is validated by comparisons with the experimental results obtained for start-up operating conditions of a first-generation foil bearing of 38.1 mm diameter with static loads of 10–50 N. Theoretical predictions of the start-up torque and takeoff speed compare well with experimental results. It is also shown how manufacturing bump height errors can explain the differences between theoretical and experimental predictions. Further validations are presented for the same bearing operating at high speeds (30, 45, and 55 krpm) and heavy static loads (up to 200 N). The calculated minimum film thickness and attitude angle are compared with experimental data from the literature.

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Gas-dynamic foil bearing model

Cited by 13 publications

References 6 publications

Transient and steady state behaviour of elasto–aerodynamic air foil bearings, considering bump foil compliance and top foil inertia and flexibility: A numerical investigation

Transient and steady state behaviour of elasto–aerodynamic air foil bearings, considering bump foil compliance and top foil inertia and flexibility: A numerical investigation

Numerical computation of the main gas-dynamic bearing static characteristics for the ball gyroscope

A New Structural Bump Foil Model With Application From Start-Up to Full Operating Conditions

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