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Aidanpää, Jan-OlovORCID iD iconorcid.org/0000-0001-6016-6342
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Publications (10 of 119) Show all publications
Benti, G. B., Aidanpää, J.-O. & Gustavsson, R. (2024). Cost-Effective Design Modification of a Sleeve Bearing with Large Bearing Clearance. Applied Sciences, 14(3), Article ID 1214.
Open this publication in new window or tab >>Cost-Effective Design Modification of a Sleeve Bearing with Large Bearing Clearance
2024 (English)In: Applied Sciences, E-ISSN 2076-3417, Vol. 14, no 3, article id 1214Article in journal (Refereed) Published
Abstract [en]

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.

Place, publisher, year, edition, pages
MDPI, 2024
Keywords
hydropower, four-lobe bearing, sleeve bearing, journal bearing, vertical rotors, rotordynamics, bearing coefficient
National Category
Other Mechanical Engineering Applied Mechanics
Research subject
Machine Design
Identifiers
urn:nbn:se:ltu:diva-105019 (URN)10.3390/app14031214 (DOI)
Projects
Swedish Hydropower Centre-SVC
Funder
Swedish Energy AgencySwedish National GridEnergy ResearchLuleå University of TechnologyKTH Royal Institute of TechnologyChalmers University of TechnologyUppsala UniversityLund University
Note

Validerad;2024;Nivå 2;2024-04-08 (hanlid);

Full text license: CC BY 4.0

Available from: 2024-04-08 Created: 2024-04-08 Last updated: 2024-04-22Bibliographically approved
Rondon, D., Pääjärvi, S., Aidanpää, J.-O., Gustavsson, R. & Jeppsson, P. (2024). Three-Dimensional Modeling for Mechanical Analysis of Hydropower Generators with Floating Rotor Rim. Machines, 12(4), Article ID 268.
Open this publication in new window or tab >>Three-Dimensional Modeling for Mechanical Analysis of Hydropower Generators with Floating Rotor Rim
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2024 (English)In: Machines, E-ISSN 2075-1702, Vol. 12, no 4, article id 268Article in journal (Refereed) Published
Abstract [en]

Hydropower generators withstand multiple forces from diverse sources during operation. To ensure their stability and safe performance, numerical tools are developed to characterize their dynamic properties. Traditionally, generators are assumed to be rigid in rotordynamic analyses. However, the measurements in power stations challenge this assumption. This article proposes a novel approach to modeling hydropower generators with floating rotor rims using a three-dimensional (3-D) Finite Element Method, aiming to study their dynamic performance and properties, including natural frequencies, the modes of vibrations, and expansion due to centrifugal and electromagnetic forces, with the goal of improving the reliability of modern designs. Both this approach and employing a two-dimensional (2-D) model using curved beams result in similar in-plane natural frequencies and the expansion of the rotor rim due to centrifugal forces. However, the 3-D model can be used to calculate the out-of-plane natural frequencies and modes, to model the dynamics of complex geometries, and to perform stress evaluation and fatigue analysis.

Place, publisher, year, edition, pages
MDPI, 2024
Keywords
rotordynamics, FEM, curved beams, hydropower generator, electromagnetic forces, modeling, ring vibration
National Category
Energy Engineering Applied Mechanics
Research subject
Machine Design
Identifiers
urn:nbn:se:ltu:diva-104994 (URN)10.3390/machines12040268 (DOI)2-s2.0-85191504822 (Scopus ID)
Projects
Swedish Hydropower Centre-SVC
Note

Validerad;2024;Nivå 2;2024-06-26 (joosat);

Full text: CC BY License

Available from: 2024-04-05 Created: 2024-04-05 Last updated: 2024-06-26Bibliographically approved
Rondon, D., Aidanpää, J.-O., Gustavsson, R., Lundin, U. & Jeppsson, P. (2023). Dynamic model for hydropower generators with floating rotor rim. Mechanical systems and signal processing, 183, Article ID 109645.
Open this publication in new window or tab >>Dynamic model for hydropower generators with floating rotor rim
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2023 (English)In: Mechanical systems and signal processing, ISSN 0888-3270, E-ISSN 1096-1216, Vol. 183, article id 109645Article in journal (Refereed) Published
Abstract [en]

For rotordynamic analysis of hydropower units, the generator is treated as a rotating rigid body. However, previous studies have confirmed that certain designs of generators are elastic, so the complex geometry of generators cannot be considered rigid. This work produced a model of hydropower generators with floating rotor rims, consisting of a rigid hub and a flexible rotor rim coupled with flexible connections. The model takes into account the influence of centrifugal and Coriolis effects, and the electromagnetic interaction between rotor and stator. The model also reproduces the dynamics of the generator with static and dynamic eccentricities. A generator prototype was employed to test the model, showing its different applications. Once validated by empirical data, this model could be used when designing generators.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Rotordynamics, Magnetic force, Generator model, Hydropower, Dynamic modeling, Curved beam
National Category
Applied Mechanics
Research subject
Machine Design
Identifiers
urn:nbn:se:ltu:diva-88899 (URN)10.1016/j.ymssp.2022.109645 (DOI)000877355300003 ()2-s2.0-85135882306 (Scopus ID)
Projects
Swedish Hydropower Centre - SVC
Funder
Swedish Energy AgencyLuleå University of TechnologyChalmers University of TechnologyUppsala UniversityLund University
Note

Validerad;2022;Nivå 2;2022-08-19 (hanlid);

Funder: Energiforsk, Svenska Kraftnät, KTH Royal Institute of Technology

Available from: 2022-01-24 Created: 2022-01-24 Last updated: 2024-04-19Bibliographically approved
Rondon, D., Aidanpää, J.-O. & Gustavsson, R. (2023). Effects of nonlinear magnetic pole forces on the dynamics of hydropower generators with floating rotor rim. In: : . Paper presented at 16th Chaotic Modeling and Simulation International Conference (CHAOS2023), Heraklion, Crete, Greece, June 13-16, 2023.
Open this publication in new window or tab >>Effects of nonlinear magnetic pole forces on the dynamics of hydropower generators with floating rotor rim
2023 (English)Conference paper, Published paper (Refereed)
National Category
Applied Mechanics
Research subject
Machine Design
Identifiers
urn:nbn:se:ltu:diva-104995 (URN)
Conference
16th Chaotic Modeling and Simulation International Conference (CHAOS2023), Heraklion, Crete, Greece, June 13-16, 2023
Available from: 2024-04-05 Created: 2024-04-05 Last updated: 2024-04-19
Benti, G. B., Aidanpää, J.-O. & Gustavsson, R. (2023). Simplified transformation matrices of journal bearings in vertical application. Applications in Engineering Science, 15, Article ID 100147.
Open this publication in new window or tab >>Simplified transformation matrices of journal bearings in vertical application
2023 (English)In: Applications in Engineering Science, E-ISSN 2666-4968, Vol. 15, article id 100147Article in journal (Refereed) Published
Abstract [en]

Rotodynamic simulation of complex or/and large systems, for instance hydropower machines, may consist of models with many degrees of freedom and require multidisciplinary computations such as fluid-thermal-structure interactions or rotor-stator interactions due to electromagnetic forces. Simulating such systems is often computationally heavy and impractical, especially in the case of optimization or parametric study, where many iterations are required. This has, therefore, created a need for simplified dynamic models to improve computational efficiency without significantly affecting the accuracy of the simulation result. The purpose of this paper is to present simplified coordinate transformation matrices for journal bearings in vertical rotors, which require less computational effort. Matrix multiplications, which appear during coordinate transformation, were eliminated, and the bearing stiffness and damping matrices in the fixed reference frame were represented by local coefficients instead. The dynamic response of a vertical rotor with eight-shoe Tilting pad journal bearings was simulated using the proposed model for two operational conditions, i.e., when the rotor was spinning at constant and variable speeds. The results from the proposed model were compared to those from the original model and validated through experiments. The conclusion was that the presented simulation model is time efficient and can effectively be used in rotordynamic simulations and analyses.

Place, publisher, year, edition, pages
Elsevier Ltd, 2023
Keywords
Bearing coefficient, Coordinate transformation, Rotordynamics, Tilting pad journal bearing, Vertical rotor
National Category
Other Mechanical Engineering
Research subject
Machine Design
Identifiers
urn:nbn:se:ltu:diva-101362 (URN)10.1016/j.apples.2023.100147 (DOI)001076998400001 ()2-s2.0-85170036228 (Scopus ID)
Note

Validerad;2023;Nivå 2;2023-09-18 (joosat);

CC BY 4.0 License

Available from: 2023-09-18 Created: 2023-09-18 Last updated: 2024-04-22Bibliographically approved
Rondon, D., Aidanpää, J.-O. & Gustavsson, R. (2022). Dynamic Model for Hydropower Generators with Floating Rotor-Rim. In: Pär Jonsén; Lars-Göran Westerberg; Simon Larsson; Erik Olsson (Ed.), Svenska Mekanikdagar 2022: . Paper presented at Svenska Mekanikdagarna 2022, Luleå, Sweden, June 15-16, 2022. Luleå tekniska universitet
Open this publication in new window or tab >>Dynamic Model for Hydropower Generators with Floating Rotor-Rim
2022 (English)In: Svenska Mekanikdagar 2022 / [ed] Pär Jonsén; Lars-Göran Westerberg; Simon Larsson; Erik Olsson, Luleå tekniska universitet, 2022Conference paper, Oral presentation with published abstract (Refereed)
Place, publisher, year, edition, pages
Luleå tekniska universitet, 2022
National Category
Applied Mechanics
Research subject
Machine Design
Identifiers
urn:nbn:se:ltu:diva-95142 (URN)
Conference
Svenska Mekanikdagarna 2022, Luleå, Sweden, June 15-16, 2022
Available from: 2023-01-03 Created: 2023-01-03 Last updated: 2023-09-05Bibliographically approved
Rondon, D., Aidanpää, J.-O. & Gustavsson, R. (2022). Effect of unbalancing mass placement in hydropower generators with floating rotor rim. In: 31st IAHR Symposium on Hydraulic Machinery and Systems 26/06/2022 - 01/07/2022 Trondheim, Norway: . Paper presented at 31st Symposium on Hydraulic Machinery and Systems (IAHR 2022), Trondheim, Norway, June 26 - July 1, 2022. Institute of Physics Publishing (IOPP) (1), Article ID 012094.
Open this publication in new window or tab >>Effect of unbalancing mass placement in hydropower generators with floating rotor rim
2022 (English)In: 31st IAHR Symposium on Hydraulic Machinery and Systems 26/06/2022 - 01/07/2022 Trondheim, Norway, Institute of Physics Publishing (IOPP) , 2022, no 1, article id 012094Conference paper, Published paper (Refereed)
Abstract [en]

Dynamic models for hydropower generators treat the rotor part as a rigid body; however, many studies have shown the opposite. The electromagnetic force distribution of deformed rotors is uneven, creating Unbalance Magnetic Pull, causing high forces on generator components leading to a risk of fatigue, therefore shortening the life of machines. Unbalancing masses can worsen the asymmetries of the rotor, which would further increase the effect of the electromagnetic interactions. This paper evaluates the rotor response using different unbalancing masses at the rotor and at the poles to quantify their impact in displacements and exciting frequencies. The model employed in this paper is based on the equation of motion derived using Lagrange equations in both co-rotating and stationary frames of reference, considering the effects of Centrifugal loads, Coriolis, and magnetization of poles. Different unbalancing mass placements affect different variables; extra weights in the poles contribute predominantly to the deformation of the rim, while the unbalance in the shaft affects the position of the shaft; a combination of placements was also studied. The simulations were performed and compared with and without radial electromagnetic forces, showing how the presence of magnetized poles further deforms the shapes of the rotor.

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2022
Series
IOP Conference Series: Earth and Environmental Science, ISSN 1755-1307, E-ISSN 1755-1315 ; 1079
National Category
Applied Mechanics
Research subject
Machine Design
Identifiers
urn:nbn:se:ltu:diva-94712 (URN)10.1088/1755-1315/1079/1/012094 (DOI)2-s2.0-85141802042 (Scopus ID)
Conference
31st Symposium on Hydraulic Machinery and Systems (IAHR 2022), Trondheim, Norway, June 26 - July 1, 2022
Projects
Swedish Hydropower Centre - SVC
Funder
Swedish Energy AgencySwedish National GridLuleå University of TechnologyKTH Royal Institute of TechnologyChalmers University of TechnologyUppsala UniversityLund University
Available from: 2022-12-21 Created: 2022-12-21 Last updated: 2024-04-19Bibliographically approved
Benti, G. B., Gustavsson, R. & Aidanpää, J.-O. (2022). Experimental Investigation on Dynamics of a Flexible Rotor. In: Pär Jonsén; Lars-Göran Westerberg; Simon Larsson; Erik Olsson (Ed.), Svenska Mekanikdagar 2022: . Paper presented at Svenska Mekanikdagarna 2022, Luleå, Sweden, June 15-16, 2022. Luleå tekniska universitet
Open this publication in new window or tab >>Experimental Investigation on Dynamics of a Flexible Rotor
2022 (English)In: Svenska Mekanikdagar 2022 / [ed] Pär Jonsén; Lars-Göran Westerberg; Simon Larsson; Erik Olsson, Luleå tekniska universitet, 2022Conference paper, Oral presentation with published abstract (Refereed)
Place, publisher, year, edition, pages
Luleå tekniska universitet, 2022
National Category
Applied Mechanics
Research subject
Machine Design
Identifiers
urn:nbn:se:ltu:diva-95071 (URN)
Conference
Svenska Mekanikdagarna 2022, Luleå, Sweden, June 15-16, 2022
Available from: 2022-12-29 Created: 2022-12-29 Last updated: 2024-04-08Bibliographically approved
Benti, G. B., Rondon, D., Gustavsson, R. & Aidanpää, J.-O. (2022). Numerical and experimental study on the dynamic bearing properties of a four-pad and eight-pad tilting pad journal bearings in a vertical rotor . Journal of energy resources technology, 144(1)
Open this publication in new window or tab >>Numerical and experimental study on the dynamic bearing properties of a four-pad and eight-pad tilting pad journal bearings in a vertical rotor 
2022 (English)In: Journal of energy resources technology, ISSN 0195-0738, E-ISSN 1528-8994, Vol. 144, no 1Article in journal (Refereed) Published
Abstract [en]

In this paper, the dynamics of tilting pad journal bearings with four and eight pads are studied and compared experimentally and numerically. The experiments are performed on a rigid vertical rotor supported by two identical bearings. Two sets of experiments are carried out under similar test setup. One set is performed on a rigid rotor with two four-pad bearings, while the other is on a rigid rotor with two eight-pad bearings. The dynamic properties of the two bearing types are compared with each other by studying the unbalance response of the system at different rotor speeds. Numerically, the test rig is modeled as a rigid rotor and the bearing coefficients are calculated based on Navier-Stokes equation. A nonlinear bearing model is developed and used in the steady state response simulation. The measured and simulated displacement and force orbits show similar patterns for both bearing types. Compared to the measurement, the simulated mean value and range (peak-to-peak amplitude) of the bearing force deviate with a maximum of 16 % and 38 %, respectively. It is concluded that, unlike the eight-pad TPJB, the four-pad TPJB excite the system at the third and fifth-order frequencies, which are due to the number of pads, and the amplitudes of these frequencies increase with the rotor speed. 

Place, publisher, year, edition, pages
American Society of Mechanical Engineers (ASME), 2022
Keywords
Bearing Stiffness, Damping Coefficient, Tilting Pad Journal Bearing, Vertical Rotor
National Category
Applied Mechanics
Research subject
Machine Design
Identifiers
urn:nbn:se:ltu:diva-86610 (URN)10.1115/1.4052032 (DOI)000720985000020 ()2-s2.0-85137204906 (Scopus ID)
Note

Validerad;2021;Nivå 2;2021-09-01 (johcin)

Available from: 2021-08-16 Created: 2021-08-16 Last updated: 2024-04-22Bibliographically approved
Rondon, D., Benti, G. B., Aidanpää, J.-O. & Gustavsson, R. (2022). Rotordynamic Characterization of Tilting-Pad Bearings With Eight Pads in Vertical Rotors . Journal of energy resources technology, 144(1), Article ID 010902.
Open this publication in new window or tab >>Rotordynamic Characterization of Tilting-Pad Bearings With Eight Pads in Vertical Rotors 
2022 (English)In: Journal of energy resources technology, ISSN 0195-0738, E-ISSN 1528-8994, Vol. 144, no 1, article id 010902Article in journal (Refereed) Published
Abstract [en]

It has been documented that stiffness and damping for a four-pad bearing are dependent not only on the magnitude of the load but also on the position of the rotor in the bearing. However, eight-pad bearings are not commonly employed on horizontal turbines, and the presence of several pads in the bearing will decisively affect the dynamics of the system. This paper evaluates the stiffness and damping coefficients of tilting-pad bearings with eight pads and explores the main frequencies acting on the forced response of a vertical rotor. The bearing properties were modeled as a function of eccentricity and position in the stationary coordinate system by Navier–Stokes equations whose results are taken from commercial software. The simulated unbalanced response is compared to experimental results; the changing position of the shaft produces a periodic stiffness and damping, which is dependent on the number of pads. Cross-coupled coefficients influence is discussed, showing that their absence makes an accurate model for the mean values. The results indicate that simulation of vertical rotors with eight-pad bearings can be simplified which allow more effective simulations and dynamic analysis. 

Place, publisher, year, edition, pages
American Society of Mechanical Engineers (ASME), 2022
Keywords
tilting-pad bearing, vertical rotor
National Category
Applied Mechanics
Research subject
Machine Design
Identifiers
urn:nbn:se:ltu:diva-86562 (URN)10.1115/1.4051803 (DOI)000720985000005 ()2-s2.0-85121689564 (Scopus ID)
Funder
Swedish Energy AgencyLuleå University of Technology
Note

Validerad;2022;Nivå 2;2022-01-01 (johcin)

Available from: 2021-08-12 Created: 2021-08-12 Last updated: 2024-04-19Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-6016-6342

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