Mode shape degeneration in linear rotor dynamics for turbocharger systems

Koutsovasilis, Panagiotis

doi:10.1007/s00419-016-1210-0

Cited by 8 publications

(5 citation statements)

References 14 publications

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“…The second case will be referred in the results as ''Direct Solution'', while the first as "Database Method". The reader may advise recent works on enhanced bearing models and rotordynamics of automotive turbochargers, including phenomena and methods which are beyond the scope of this paper [21][22][23][24][25][26][27][28][29][30][31].…”

Section: Application In a High-speed System Of Automotive Turbochargermentioning

confidence: 99%

Evaluation of Transient Response of Turbochargers and Turbines Using Database Method for the Nonlinear Forces of Journal Bearings

Chasalevris

Louis

2019

Lubricants

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The paper extents the fluid film bearing database method to arbitrary fixed bearing profiles including floating ring bearings. The method is applied to evaluate rotordynamic response of an automotive turbocharger, modeled as rigid rotor, and of a turbine-generator shaft train for power generation modeled as flexible rotor through the transient transfer matrix method. The methodology claims to render drastically faster evaluation of transient response of rotating systems with nonlinear bearings regardless the complexity of the bearing models implemented. The computational time of transient response is similar to this when short bearing expressions are used. Turbocharger rotordynamic simulation considers the use of nonlinear bearing models as mandatory, and several case studies have to be performed for the definition of key design parameters of floating ring bearings. The bearing database method offers the tool for a severe total time reduction in rotordynamic calculations, with the possibility to implement advanced thermohydrodynamic bearing models to the rotordynamic algorithm as fast as short bearing approximation formulas. Furthermore, the rotordynamic design of large turbine shaft trains is still based on linear harmonic analysis which leads to conservative designs. The database method aims to include the transient response of nonlinear rotor models as a standard procedure in the rotordynamic design of large shaft trains, which nowadays is avoided due to high time cost and complexity.

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Section: Application In a High-speed System Of Automotive Turbochargermentioning

confidence: 99%

Evaluation of Transient Response of Turbochargers and Turbines Using Database Method for the Nonlinear Forces of Journal Bearings

Chasalevris

Louis

2019

Lubricants

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“…Vibration analysis plays an important role in the fault diagnosis of high-speed rotary asymmetric rotor equipment. According to statistics, about 60% of high-speed rotary equipment vibration problems are caused by Symmetry 2021, 13, 1054 2 of 13 asymmetric rotor imbalance [3,[5][6][7]. The unbalance of the asymmetric rotors means that centroids of the asymmetric rotors deviate from their rotation centerline so that a certain centrifugal force will be generated when the asymmetric rotors rotate at a high speed [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

“…The unbalance of the asymmetric rotors means that centroids of the asymmetric rotors deviate from their rotation centerline so that a certain centrifugal force will be generated when the asymmetric rotors rotate at a high speed [4][5][6]. This centrifugal force is transmitted to the bearing parts such as the gearbox through the bearing base, causing the equipment to vibrate [7][8][9]. Therefore, the study of highspeed rotary equipment vibration optimization is of great significance to its development and application.…”

Section: Introductionmentioning

confidence: 99%

Multistage Asymmetric Rotors Coaxial Measurement Stacking Method Based on Minimization of Exciting Force

et al. 2021

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The unbalanced exciting force of high-speed rotary asymmetric rotor equipment is the main factor causing rotor vibration. In order to effectively suppress the vibration of the asymmetric rotor equipment, the paper establishes a multistage asymmetric rotor coaxial measurement stacking method that minimizes the exciting force. By analyzing the propagation process of the centroid of the multistage asymmetric rotor assembly and analyzing the relationship between the geometric center and the centroid of a single asymmetric rotor, a multistage asymmetric unbalanced rotor propagation model based on geometric center stacking is established. The genetic algorithm is used to optimize the unbalance of the multistage asymmetric rotors. Combined with the vibration principle under the exciting force, the vibration amplitude of the left bearing at different rotation speeds under the minimization of the exciting force and the random assembly phase is analyzed. Finally, the experimental asymmetric rotors are dynamically measured, combined with the asymmetric rotors’ geometric error measurement experiment. The experimental results confirm that the vibration amplitude of the assembly phase with the minimum exciting force is smaller than the vibration amplitude under the random assembly phase at three-speed modes, and the optimization rate reached 73.2% at 9000 rpm, which proves the effectiveness of the assembly method in minimizing the exciting force.

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“…The dynamic analysis of the centrifugal pump rotor is important and essential for a centrifugal pump system. In order to reduce the research difficulty, a linear model has been often applied in the investigation into dynamic characteristics of a rotor system, such as critical speeds, mode shape as well as unbalanced responses, as mentioned in [1][2][3][4][5][6]. For some structures, when the vibration response is small, the linear model may be sufficient for a dynamic analysis of a centrifugal pump rotor.…”

Section: Introductionmentioning

confidence: 99%

Research on Steady-State Characteristics of Centrifugal Pump Rotor System with Weak Nonlinear Stiffness

Zhou

Qiu

Zhang

et al. 2018

TFAMENA

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Steady-state vibration response characteristics of a motion model of a centrifugal pump rotor system with weak nonlinear stiffness have been calculated by using the multiple scale method (MSM). The theoretical results were in good agreement with the numerical results. Based on the MSM and the numerical method, the effects of detuning parameter, nonlinear stiffness parameter and natural frequency on steady-state amplitude were also investigated. Finally, Lyapunov's theorem on stability in the first approximation was applied for the determination of the system's stable and unstable solution regions. The calculated results imply that the centrifugal pump rotor system with weak nonlinear stiffness exhibits typical nonlinear vibration characteristics. The variation of detuning parameter, nonlinear stiffness parameter and natural frequency can result in a jump phenomenon, and their corresponding curves present 'hard spring', 'soft spring' and 'S'-shaped amplitude characteristic, respectively. Smaller detuning parameter and natural frequency or greater nonlinear stiffness parameter are beneficial to decreasing the steady-state response amplitude. The results can provide reference for an investigation into nonlinear vibration characteristics of a centrifugal pump rotor system.

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Mode shape degeneration in linear rotor dynamics for turbocharger systems

Cited by 8 publications

References 14 publications

Evaluation of Transient Response of Turbochargers and Turbines Using Database Method for the Nonlinear Forces of Journal Bearings

Evaluation of Transient Response of Turbochargers and Turbines Using Database Method for the Nonlinear Forces of Journal Bearings

Multistage Asymmetric Rotors Coaxial Measurement Stacking Method Based on Minimization of Exciting Force

Research on Steady-State Characteristics of Centrifugal Pump Rotor System with Weak Nonlinear Stiffness

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