Improving stability and operation of turbine rotors using adjustable journal bearings

Chasalevris, Athanasios; Dohnal, Fadi

doi:10.1016/j.triboint.2016.06.022

Cited by 50 publications

(17 citation statements)

References 19 publications

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“…Direct and indirect actions of control forces onto the rotating shaft can occur either via bearing housing and bushing [19][20][21][22][23][24][25][26][27][28][29] or via bearing clearance [13][14][15][16][17][18]27]. The control actions influence fundamentally four parameters: either the bearing gap function h(θ) [21][22][23][24][25][26] and its gradient dh/dθ [23][24][25], or the fluid viscosity µ [30][31][32], or the fluid film pressure field p(θ) [13][14][15][16][17][18]27]. All four parameters are directly and explicitly written in the Reynolds and Energy equations and significantly affect the bearing properties.…”

Section: Strategies For Rendering Adaptability and Multi-functionalitmentioning

confidence: 99%

Controllable Sliding Bearings and Controllable Lubrication Principles—An Overview

Santos

2018

Lubricants

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Hydrodynamic and aerodynamic lubrication regimes in their controllable forms have been intensively investigated over the last two decades. With the aim of reducing friction and improving thermal, static, and dynamic characteristics of radial sliding bearings, different types of electro-mechanical actuators have been coupled to such bearings. Depending on (i) the actuator type; (ii) the actuation principle, i.e., hydraulic, pneumatic, piezoelectric or magnetic among others; and (iii) how such an actuator is coupled to the sliding bearings, different regulation and control actions of fluid film pressure and lubricant flow can be obtained. The most common actions are: (a) the control of the injection pressure to modify the fluid film pressure statically as well as dynamically; (b) the adjustment of the angle and direction of injection flow (mostly passive action); (c) the control of the sliding bearing gap and its preload via moveable and compliant sliding surfaces; and (d) the control of the lubricant viscosity. All four parameters, i.e., pressure, flow (velocity profiles), gap and viscosity, are explicit parameters in the modified form of Reynolds' equations for active lubrication. In this framework, this paper gives one main original contribution to the state-of-the-art of radial sliding bearings and controllable lubrication: a comprehensive overview about the different types of controllable sliding bearings and principles used by several authors. The paper ends with some conclusive remarks about advantages and drawbacks of the different design solutions for controllable sliding bearings and the main challenges to be overcome towards industrial applications.

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Section: Strategies For Rendering Adaptability and Multi-functionalitmentioning

confidence: 99%

Controllable Sliding Bearings and Controllable Lubrication Principles—An Overview

Santos

2018

Lubricants

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“…For example, it was found that high-speed cutting power loss due to friction in the hydrostatic spindle bearing can exceed cutting power (Wardle, 2015;Chasalevris et al, 2016). Search of rational design solutions for units of friction and bearing lubrication systems is determined to minimize energy loss.…”

Section: Promising Ways Of Energy Efficiency Gain Of Spindles With Flmentioning

confidence: 99%

Increasing of Energy Efficiency of Spindles with Fluid Bearings

Fedorynenko

Sapon

Boyko

et al. 2017

Acta Mechanica Et Automatica

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Promising ways of energy efficiency gain of spindles with fluid flow bearings are offered. New design of journal hybrid flow bearing which contains spherical bearing pockets and adjustable valves with relay control system is offered to improve energy efficiency of spindle units of machine tools. To reduce power losses of fluid bearings at high speed special lubrication based on water with integrated system of corrosion protection is offered. Results of theoretical research of energy consumption of grinding machine tool with a new design of spindle hybrid bearings are presented. Power losses of the spindle unit with both new design and base design of journal bearings are assessed. Effectiveness of new design of spindle hybrid bearings at high operating speeds is shown.

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“…In addition, various types of dampers are used for the rotor vibration attenuation, for example, the magnetorheological squeeze film damper was utilized to reduce the rotor vibration by Hemmatian and Ohadi. 8 The bearing parameters can be self-adjusted by the tilting-pad journal bearing, and it is suitable to suppress the oil film whirl and whip occurring in the rotor system; for example, Chasalevris and Dohnal, 9,10 Santos and colleagues, [11][12][13] and Queiroz et al 14 investigated the active tilting-pad journal bearing and the active fluid-film bearing to extend the stability margins for the rotor system. Another example of the parameter adjusting is the seal parameter adjusting.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear dynamic behavior and stability of a rotor/seal system with the dynamic vibration absorber

Niu

Yao

et al. 2019

Advances in Mechanical Engineering

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The dynamic vibration absorbers have been applied to attenuate the critical or unbalanced vibration but may create the fluid-induced vibration instability in the rotor/seal system. The major purpose of this study is devoted to the effects of the dynamic vibration absorber on the nonlinear dynamic behavior and stability of the fluid-induced vibration in the rotor/seal system. The dynamic vibration absorber is attached on the shaft in the perpendicular directions. The model of the rotor/seal-dynamic vibration absorber system is established as the modified Jeffcott rotor system, and Muszynska nonlinear seal force is applied. The numerical method is used for the dynamic behavior analysis. The effects of the natural frequency and damping ratio of the dynamic vibration absorber on the dynamic behavior are discussed. The stability of the rotor/seal-dynamic vibration absorber system is judged by the eigenvalue theory. The variations of the instability threshold with the parameters of the dynamic vibration absorber are obtained. The results show that the instability threshold and instability vibration frequency are changed by the dynamic vibration absorber. The parameters of the dynamic vibration absorber must be selected carefully to avoid reducing the instability threshold and causing the instability vibration to occur in advance when the dynamic vibration absorber is applied to attenuate the critical or unbalanced vibration of the rotor/seal system.

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Improving stability and operation of turbine rotors using adjustable journal bearings

Cited by 50 publications

References 19 publications

Controllable Sliding Bearings and Controllable Lubrication Principles—An Overview

Controllable Sliding Bearings and Controllable Lubrication Principles—An Overview

Increasing of Energy Efficiency of Spindles with Fluid Bearings

Nonlinear dynamic behavior and stability of a rotor/seal system with the dynamic vibration absorber

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