Numerical methods for theoretical analysis of foil bearing dynamics

Tkacz, Eliza; Kozanecki, Zbigniew; Kozanecka, Dorota

doi:10.1016/j.mechrescom.2017.01.009

Cited by 8 publications

(8 citation statements)

References 6 publications

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“…Among the technologies used successfully, one of them stands out with particularly interesting results and simple modeling: the technology of MITI-type stacking bearings [13]. Numerous numerical and experimental studies are interested in the static and dynamic characteristics of this type of bearings [4][5][6][7][8]14]. These papers focused on two areas:…”

Section: Mohawk Innovative Technology Incorporated (Miti) Technologymentioning

confidence: 99%

“…One of the objectives was to validate their thermomechanical behavior at high temperatures [1,2]. Currently, the fields of application are more extensive but still concern the guidance of shafts rotating at very high speed, withstanding moderate loads and subjected to sometimes severe thermal stresses [3][4][5][6][7][8]. Some of them [3,5,9] consider the coupling between the bearing and the rotor with deformation of the sheets and friction between the sheets and the support using complex and numerically time-consuming approaches.…”

Section: Introductionmentioning

confidence: 99%

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Dynamic Performances of Foil Bearing Supporting a Jeffcot Flexible Rotor System Using FEM

et al. 2020

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Aerodynamic bearings have received considerable attention in recent decades and are increasingly being used in applications where high speed, low loads and high precision are required. Aerodynamic applications mainly concern auxiliary power units (APU) and air-conditioning machines (ACM). From the industrial point of view, the static and dynamic characteristics of these bearings rotating at very high speed must be determined. According to the literature, studies carried out on this type of bearing consider the elastic deformations of the foils due to the pressure generated in the air film. The linear approach is from time to time adopted for the prediction of the dynamic behavior of these bearings, which is not always justified. This paper aims to present a step towards a better mastery of the non-linear dynamic behavior of a flexible rotor-air bearing system. We will focus on finite element modeling (FEM) of the non-linear isothermal elasto-aerodynamic lubrication problem in the case of a radial bearing operating in a dynamic regime. We will present the effects of rotational speed, unbalance eccentricity, and rotor mass on the non-linear response of rigid and compliant bearings. We use a partitioned approach which treats fluid and structure as two computation domains solved separately; reducing the development time needed for a monolithic code which is difficult to manage when the geometries or the physical properties of the problem to be treated become complex.

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Section: Mohawk Innovative Technology Incorporated (Miti) Technologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dynamic Performances of Foil Bearing Supporting a Jeffcot Flexible Rotor System Using FEM

et al. 2020

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“…9 By using the finite element method and transfer matrix method, Chasalevris and Papadopoulos studied a rotor bearing system that consists of a multisegment continuous rotor and plain fluid film bearings with finite length, and the interaction effect between the rotating shaft and the fluid film forces on the nonlinear behavior was discussed. 10 Tkacz et al studied the stability of a self-acting, gas bearing with a flexibly supported foil, and a spring-damper model was selected for the fluid film analysis. 11 The inner and the outer race centers are not assumed to be collinear when the relation for deflections in the rolling element is developed.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear dynamic analysis of worn oil-lubricated rolling bearings

Fang¹,

Liu

Yang³

2020

Proceedings of the Institution of Mechanical Engineers, Part E:

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Based on the elastohydrodynamic theory, the nonlinear dynamic behavior of worn oil-lubricated rolling bearings is explored, and the dynamic response including the effect of trajectory of the axis center, the accelerated speed, and the film thickness is analyzed. The worn model is represented by the worn depth. The discrete iterative method and implicit Euler method are combined to solve the dynamic equations. In numerical examples, the trajectory of the axis center, the accelerated speed and the film thickness under different worn depths are discussed. It is found that the stabilized point shows significant variation with the worn depth, and the wear effect is also quite related with the rolling speed. The trajectory of the axis center of worn bearing subjected to a step load is also examined in detail.

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“…ORC microturbines can use bearing systems equipped in bearings of many different types, such as, for example, rolling bearings, bearings lubricated with a low-boiling medium in the liquid or gaseous state or foil bearings-which are increasingly considered as potential solutions. The numerical calculations of foil bearings are described, for example, in article [8]. Static and dynamic analyses of foil bearings are presented in paper [9] while an assessment of dynamic properties of a rotor supported by such bearings can be found in publication [10].…”

Section: Introductionmentioning

confidence: 99%

Selection of the oil-free bearing system for a 30 kW ORC microturbine

Breńkacz¹,

Żywica²,

Bogulicz³

2019

J. vibroeng.

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The article discusses results of the analyses of various bearing systems for the rotor of an ORC (Organic Rankine Cycle) microturbine with an electric power of 30 kW. It is impossible to choose the appropriate bearing system taking into account only basic parameters of the bearings. When designing a new power turbine, it is important to conduct the dynamic and strength analysis of the entire rotor-bearings-supporting structure system. The nominal rotational speed of the newly designed single-stage axial-flow turbine is 40,000 rpm. The turbine will be powered using the vapour of a low-boiling working medium. The chosen working medium cannot be used in combination with all materials that are commonly used for turbine constructions. An additional requirement was that the turbogenerator must be oil-free. The temperature of the working medium directed to the rotor blades could exceed a value of 200 °C. Three bearing systems were considered: bearings lubricated with a low-boiling fluid (in the liquid form), gas bearings lubricated with the vapour of a low-boiling medium and rolling bearings. Since the rotors used in those three systems have different geometries, their dynamic properties vary as well. The rotor dynamics analyses were carried out using computer programs belonging to the MESWIR environment, which had been developed at the Institute of Fluid-Flow Machinery of the Polish Academy of Sciences (IMP PAN) in Gdańsk. The computational model, based on the finite element method, was used to prepare graphs on which are presented vibration amplitudes as functions of the rotational speed. The computational model, based on the finite element method, served to perform calculations on the basis of which graphs presenting vibration amplitudes as functions of the rotational speed were prepared. Moreover, vibration trajectories of individual nodes of the computational model were shown. Besides analyses of the bearings themselves, calculations were also carried out to assess the dynamic properties of the rotors supported by those bearings in a wide range of rotational speeds. As a result of the conducted analyses, the concept of an innovative turbogenerator was created. Its rotor can operate at a very high rotational speed, and the bearings do not require oil lubrication.

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Numerical methods for theoretical analysis of foil bearing dynamics

Cited by 8 publications

References 6 publications

Dynamic Performances of Foil Bearing Supporting a Jeffcot Flexible Rotor System Using FEM

Dynamic Performances of Foil Bearing Supporting a Jeffcot Flexible Rotor System Using FEM

Nonlinear dynamic analysis of worn oil-lubricated rolling bearings

Selection of the oil-free bearing system for a 30 kW ORC microturbine

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