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Advanced Technologies in Rotating Machinery: Design, Modeling, Manufacturing, Testing, and Operation

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Robotics and Automation".

Deadline for manuscript submissions: closed (20 April 2025) | Viewed by 8274

Special Issue Editor

Department of Mechanical Engineering, Hanyang University, Ansan 15588, Gyeonggi-do, Korea
Interests: turbomachinery rotordynamics; rotating machinery diagnostics and vibration; bearings, seals, and dampers for turbomachinery; advanced turbomachinery with improved stability; cryogenic bearings for liquid rocket engine turbopumps; oil-free turbomachinery; rocket engine turbopumps; electrically assisted turbomachinery; automotive turbochargers; high-speed electric motors/generators; space tribology
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Special Issue Information

Dear Colleagues,

Rotating machinery or turbomachinery is a machine with a rotating component that transfers energy to a fluid or vice versa. Consequently, in a turbomachine, there is energy transfer between the fluid and the rotor through dynamic interaction.

The current Special Issue invites archival-quality papers focused on the broad topic of component and system technologies for rotating machinery. We hope to establish a collection of papers that will be of interest to scholars in the field. Contributions in the form of full papers, reviews, and communications about the related topics are very welcome.

Dr. Keun Ryu
Guest Editor

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Keywords

  • computational fluid dynamics (CFD) analysis
  • controls, diagnostics, instrumentation, and measurement techniques
  • heat transfer and thermal management
  • new propulsion and power systems
  • steam turbines
  • structures and dynamics
  • advanced gas turbine engines and cycles, and gas turbine hybrids
  • advanced manufacturing concepts for gas turbine engines
  • advances in exhaust technologies (diffusers, nozzles, and related systems)
  • combustors, fuel injectors, alternative fuels, emissions, fuel flexible combustion systems
  • engine controls, operability, and propulsion health management
  • high-fidelity simulations and validation experiments
  • high-speed low pressure turbines
  • multidisciplinary design, analysis/optimization of engine systems and components
  • thermal management, heat transfer and cooling, materials, and coatings
  • rotor dynamics
  • machine components in turbomachinery
  • aerodynamic design, analysis, and test of compressor and turbine blading
  • compressor stall and surge
  • aeromechanical instabilities

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Related Special Issue

Published Papers (5 papers)

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Research

15 pages, 10248 KiB  
Article
Flow-Induced Fatigue Damage of Large Francis Turbines Under Multiple Operating Loads
by Pinghu Liu, Xingxing Huang, Tianyu Yang and Zhengwei Wang
Appl. Sci. 2024, 14(24), 12003; https://doi.org/10.3390/app142412003 - 21 Dec 2024
Cited by 2 | Viewed by 986
Abstract
The Francis runner is a critical component of the Francis turbine generator unit, playing a central role in converting water energy into rotating mechanical energy that drives the generator in hydropower stations. In-depth analyses of the flow characteristics of the Francis runner under [...] Read more.
The Francis runner is a critical component of the Francis turbine generator unit, playing a central role in converting water energy into rotating mechanical energy that drives the generator in hydropower stations. In-depth analyses of the flow characteristics of the Francis runner under various operating conditions and avoiding fatigue damage of the Francis runner are crucial to the reliability and efficiency of hydropower operation. In this paper, the flow dynamics of a large Francis turbine runner are analyzed under three representative loading conditions—low partial load, high partial load, and full load—and the flow-induced stress of the runner is analyzed under these loading conditions. It was found that the maximum static and dynamics stresses of the runner at three representative loading conditions are located at the chamfered surface where the blade trailing edge connects to the runner crown. The maximum static stresses of the Francis runner are 284 MPa, 352 MPa, and 381 MPa at low partial load, high partial load, and full load, respectively, and they are above the allowable stress limits, as half of the yield stress of the runner material of 550 MPa. The peak-to-peak values of runner dynamic stress at low partial load, high partial load, and full load are 15 MPa, 25 MPa, and 14.6 MPa, respectively. The high stress invoked by the unsteady flow under various loading conditions in this runner was the cause of the fatigue breakage of the runner blades. The results of this investigation have important reference values for mitigating fatigue damage in similar Francis runners and optimizing unit operation. Full article
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18 pages, 31070 KiB  
Article
Flow-Induced Stress Analysis of a Large Francis Turbine Under Different Loads in a Wide Operation Range
by Xingxing Huang, Hua Ou, Hao Huang, Zhengwei Wang and Gang Wang
Appl. Sci. 2024, 14(24), 11782; https://doi.org/10.3390/app142411782 - 17 Dec 2024
Cited by 3 | Viewed by 930
Abstract
Francis turbines, being widely used in hydropower plants, operate under different loads which significantly affect their hydraulic characteristics and structural dynamics. It is essential to carry out the flow-induced dynamics analysis of the large prototype Francis turbines under different loads in a wide [...] Read more.
Francis turbines, being widely used in hydropower plants, operate under different loads which significantly affect their hydraulic characteristics and structural dynamics. It is essential to carry out the flow-induced dynamics analysis of the large prototype Francis turbines under different loads in a wide load operation range to optimize the hydraulic performance, ensure structural reliability, and prevent mechanical failure. This work analyzes the flow-induced dynamics of a large Francis turbine prototype with a rated power of 46 MW. Computer-aided design (CAD) models of the Francis turbine unit are first constructed, including the fluid and structural domains. After generating the computational meshes of the flow passages in the Francis turbine unit, Computational fluid dynamics (CFD) calculations are carried out under four typical operating conditions from 25% load to 100% load, and the pressure files obtained from CFD calculations are applied to the finite element model to analyze the flow-induced stresses of the runner. The results show that the pressure inside the Francis turbine runner decreases gradually from the spiral case to the draft tube under 25%, 50%, 75%, and 100% loads, but the local pressure distribution in the crown chamber of the Francis turbine unit varies under different loads. The locations of the maximum stress of the runner under the four different operating conditions vary with the power output. The flow-induced maximum stress of the runner at 25% load is located on the chamfer of the connection between the blade trailing edge and the crown. But from 50% load to 100% load, the maximum stress of the runner appears on the chamfer of the connection between the blade leading edge and the band. From 25% load to full load, the maximum stress of the unit is one-fifth of the yield stress of the runner material, and the runner will not be damaged during normal use. The calculation method with a fully three-dimensional fluid–structure interaction (FSI) method and the conclusions proposed in this study can provide important references for the design and evaluation of other hydraulic turbine units. Full article
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17 pages, 11701 KiB  
Article
Experimental Flow Performance Investigation of Francis Turbines from Model to Prototype
by Baig Mirza Umar, Xingxing Huang and Zhengwei Wang
Appl. Sci. 2024, 14(17), 7461; https://doi.org/10.3390/app14177461 - 23 Aug 2024
Cited by 2 | Viewed by 2529
Abstract
Investigating the flow performance of Francis turbines from model to prototype is a complex but essential process for ensuring reliable and efficient turbine operation in hydropower plants. It ensures that Francis turbine designs operate efficiently under various operating conditions, extending from laboratory reduced-scale [...] Read more.
Investigating the flow performance of Francis turbines from model to prototype is a complex but essential process for ensuring reliable and efficient turbine operation in hydropower plants. It ensures that Francis turbine designs operate efficiently under various operating conditions, extending from laboratory reduced-scale models to full-scale prototype installations. In this investigation, a Francis turbine model was tested under different operating conditions, and its properties were measured, including torque, hydraulic efficiency, power output, cavitation coefficient, rotational speed, flow rate, and pressure pulsations. The results of the Francis turbine model test indicate that it achieved the maximum torque with the designed discharge and designed head. The cavitation coefficient consistently remained higher than the critical cavitation coefficient. The initial cavitation bubbles were observed at 50% partial load but disappeared at full load. Pressure pulsations under different operating conditions showed the maximum peak-to-peak amplitude appearing at the turbine inlet domain and the minimum amplitude occurring at the draft tube elbow. A hill chart shows that the model’s best efficiency was 93.66%, and the estimated best efficiency of the prototype was 95.03% at the design head. The conclusions and methodology of this study can be generalized to other similar hydraulic turbines, especially prototype Francis turbines that lack experimental results. Full article
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16 pages, 6835 KiB  
Article
Determining Steady-State Operation Criteria Using Transient Performance Modelling and Steady-State Diagnostics
by Konstantinos Mathioudakis, Nikolaos Aretakis and Alexios Alexiou
Appl. Sci. 2024, 14(7), 2863; https://doi.org/10.3390/app14072863 - 28 Mar 2024
Viewed by 1627
Abstract
Data from the steady-state operation of gas turbine engines are used in gas path diagnostic procedures. A method to identify steady-state operation is thus required. This paper initially explains and demonstrates the factors that cause a deviation in engine health when transient data [...] Read more.
Data from the steady-state operation of gas turbine engines are used in gas path diagnostic procedures. A method to identify steady-state operation is thus required. This paper initially explains and demonstrates the factors that cause a deviation in engine health when transient data are used for diagnosis and shows that there is a threshold in the slope of time traces, below which the variation in engine health parameters is acceptable. A methodology for deriving a criterion for steady-state operation based on actual flight data is then presented. The slope of the exhaust gas temperature variation with time and the size of its time-series window, from which this slope is determined, are the required parameters that must be specified when applying this criterion. It is found that the values of these parameters must be selected so that a sufficient number of steady-state points are available without compromising the accuracy of the diagnostic procedure. Full article
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17 pages, 3930 KiB  
Article
Cost-Effective Design Modification of a Sleeve Bearing with Large Bearing Clearance
by Gudeta Berhanu Benti, Jan-Olov Aidanpää and Rolf Gustavsson
Appl. Sci. 2024, 14(3), 1214; https://doi.org/10.3390/app14031214 - 31 Jan 2024
Cited by 1 | Viewed by 1277
Abstract
In 2015, a 45 MW vertical hydropower machine exhibited excessive vibration after refurbishment. Measurements revealed a substantial bearing clearance at the lower generator guide bearing. Consequently, the bearing was unable to generate sufficient opposing force to drive the rotor toward the bearing center, [...] Read more.
In 2015, a 45 MW vertical hydropower machine exhibited excessive vibration after refurbishment. Measurements revealed a substantial bearing clearance at the lower generator guide bearing. Consequently, the bearing was unable to generate sufficient opposing force to drive the rotor toward the bearing center, resulting in more pronounced overall system vibration. Addressing this challenge required a cost-effective and feasible solution for mitigating the vibration problem. To this end, a design modification was implemented wherein the lower generator guide bearing (originally a sleeve bearing) was modified to a four-lobe bearing by offsetting the two halves of the bearing twice in two axes. Numerical simulations and experimentations were conducted, and the dynamics of the machine before and after the design modification were investigated. Both the simulation and experimental results showed that the machine with the four-lobe bearing improved the system stability and reduced the vibration amplitudes. The numerical simulation result demonstrated that, due to the design modification, the first and second critical speeds were effectively eliminated for a speed range of up to three times the nominal speed. Furthermore, for nominal operation with unbalanced magnetic pull, the four-lobe bearing provided a stability advantage in terms of the modal parameters relative to the original sleeve bearing. Full article
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