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Design and Optimization of Rotor Dynamics in Applications

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Mechanical Engineering".

Deadline for manuscript submissions: closed (10 December 2021) | Viewed by 7267

Special Issue Editors


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Guest Editor
School of Mechanical Engineering, National Technical University of Athens, 15780 Athens, Greece
Interests: dynamics of machines and mechanisms; tribology and lubrication; adjustable bearings; nonlinear dynamics of rotating systems; turbomachinery rotordynamics

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Guest Editor
Biomedical Computer Science and Mechatronics, UMIT - University for Health Sciences, Medical Informatics and Technology, 9900 Lienz, Austria
Interests: dynamics, vibration and vibration control; multibody dynamics; nonlinear dynamics; parametric excitation; parametric instabilities; rotor dynamics; structural dynamics; time-periodic systems

Special Issue Information

Dear Colleagues,

In recent years, we have followed the progress of the research area of future turbomachines in power generation and transport, including applications such as steam and gas turbines, hydro- and wind turbines, energy storage flywheels, aircraft engines, turbochargers, turbo compressors and more. Developments are driven by problems and trends in oil-free technology, electric drive, downsizing, high speed and stability range, power loss reduction, recyclable materials, emission reduction, fuel consumption and further environmental concerns.

In some aspects of turbomachinery rotor dynamic design, the methods are mature and the tools advanced enough to provide boundary design. Other aspects require the integration of edge tools in simulation and optimization so as to establish the future design instructions of turbomachines operating beyond today’s limitations.

In this Special Issue of Applied Sciences entitled “Design and Optimization of Rotor Dynamics in Applications”, we are seeking original contributions on the broad area of the dynamic design of rotating machines. Topics include but are not limited to new rotor dynamic concepts on turbomachines, dynamic design optimization of turbomachines utilizing modern methods, nonlinear rotor dynamics, oil-free and novel bearing elements, digital twins of turbomachines, and advanced methods and principles for stability and control.

Prof. Dr. Athanasios Chasalevris
Prof. Dr. Fadi Dohnal
Guest Editors

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Keywords

  • turbomachinery rotor dynamics
  • rotor dynamic design
  • stability
  • balancing
  • nonlinear phenomena in rotor dynamics
  • bearings
  • gas foil bearings
  • oil-free technology
  • tribology
  • seals
  • blade vibrations
  • mechanical integrity of rotors, bearings and blades
  • order reduction methods
  • design optimization techniques
  • rotor dynamics and control
  • digital twins in rotor dynamics

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Published Papers (2 papers)

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Research

16 pages, 2740 KiB  
Article
Linear and Nonlinear Performance Analysis of Hydrodynamic Journal Bearings with Different Geometries
by Carlos Alberto Alves Viana, Diogo Stuani Alves and Tiago Henrique Machado
Appl. Sci. 2022, 12(7), 3215; https://doi.org/10.3390/app12073215 - 22 Mar 2022
Cited by 7 | Viewed by 3331
Abstract
In rotor dynamics, a traditional way of representing the dynamics of hydrodynamic bearings is using stiffness/damping coefficients. It is thus necessary to carry out a linearization of hydrodynamic forces around the shaft’s equilibrium position. However, hydrodynamic bearings have highly nonlinear nature, depending on [...] Read more.
In rotor dynamics, a traditional way of representing the dynamics of hydrodynamic bearings is using stiffness/damping coefficients. It is thus necessary to carry out a linearization of hydrodynamic forces around the shaft’s equilibrium position. However, hydrodynamic bearings have highly nonlinear nature, depending on operating conditions. Therefore, this paper discusses the applicability of these linear/nonlinear approaches using a computational model of the rotating system, where the finite element method is used for rotor modelling and the finite volume method for bearing calculation. The main goal is to investigate the boundaries for linear approximation of the hydrodynamic forces present in lobed hydrodynamic bearings, with the system operating under high loading conditions. Several numerical simulations were performed varying preload parameter and rotating speed. A comparison of the system’s responses, in time domain (shaft orbits) and frequency domain (full spectrum), is made for linear and nonlinear models. Results showed that trilobed bearings are more susceptible to nonlinearities, even in situations of smaller vibration amplitudes, while elliptical bearings are sensitive only under larger vibration amplitudes. These analyses are of great importance for mapping the influence of nonlinearities in different types of lobed hydrodynamic bearings with fixed geometry, varying the preload parameter to verify the influence on the system’s dynamic response. This study is important and serves as the basis for cases of monitoring and fault diagnosis (in the field of structural health monitoring) since it is crucial to distinguish what would be a fault signature or a standard nonlinear effect created by the use of hydrodynamic bearings. Full article
(This article belongs to the Special Issue Design and Optimization of Rotor Dynamics in Applications)
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19 pages, 1147 KiB  
Article
Stability Analysis of Rotor-Bearing Systems under the Influence of Misalignment and Parameter Uncertainty
by Xiaodong Sun, Kian K. Sepahvand and Steffen Marburg
Appl. Sci. 2021, 11(17), 7918; https://doi.org/10.3390/app11177918 - 27 Aug 2021
Cited by 7 | Viewed by 2908
Abstract
Stability is a well-known challenge for rotating systems supported by hydrodynamic bearings (HDBs), particularly for the condition where the misalignment effect and the parametric uncertainty are considered. This study investigates the impact of misalignment and inherent uncertainties in bearings on the stability of [...] Read more.
Stability is a well-known challenge for rotating systems supported by hydrodynamic bearings (HDBs), particularly for the condition where the misalignment effect and the parametric uncertainty are considered. This study investigates the impact of misalignment and inherent uncertainties in bearings on the stability of a rotor-bearing system. The misalignment effect is approximately described by introducing two misaligned angles. The characteristics of an HDB, such as pressure distribution and dynamic coefficients, are calculated by the finite difference method (FDM). The stability threshold is evaluated as the intersection of run-up curve and borderline. Viscosity and clearance are considered as uncertain parameters. The generalized polynomial chaos (gPC) expansion is adopted to quantify the uncertainty in parameters by evaluating unknown coefficients. The unknown gPC coefficients are obtained by using the collocation method. The results obtained by the gPC expansion are compared with those of the Monte Carlo (MC) simulation. The results show that the characteristics of the HDB and the stability threshold are affected by misalignment and parameter uncertainties. As the uncertainty analysis using the gPC expansion is performed on a relatively small number of predefined collocation points compared with the large number of MC samples, the method is very efficient in terms of computation time. Full article
(This article belongs to the Special Issue Design and Optimization of Rotor Dynamics in Applications)
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