Numerical and experimental analysis of rubbing–misalignment mixed fault in a dual-rotor system

2020 ◽  
pp. 095440622096858
Author(s):  
Wenzhen Xie ◽  
Chao Liu ◽  
Nanfei Wang ◽  
Dongxiang Jiang
Keyword(s):  
High Speed ◽  
Experimental Tests ◽  
Rotor System ◽  
Dynamic Responses ◽  
System Model ◽  
Speed Ratio ◽  
Rotor Systems ◽  
Frequency Components ◽  
Aero Engines ◽  
Misalignment Fault

Dual-rotor systems are widely used in aero-engines, in which rubbing–misalignment mixed faults are essential, as both are frequently observed and can occur simultaneously due to the harsh working conditions of high temperature, high pressure, and high speed. To analyze the vibration characteristics of such faults, a dual-rotor system model is established and dynamic responses under varying parameters of the dual-rotor system with rubbing–misalignment mixed fault are investigated. Through numerical simulation, the effects of speed ratio, rubbing clearance, and rubbing stiffness on the dual-rotor system with rubbing–misalignment fault are revealed. Meanwhile, experimental tests are conducted for validation, the main findings of which are that the characteristic frequency components could benefit the diagnosis of mixed faults in dual-rotor systems.

scholarly journals The Dynamic Characteristic of a Faulted Rotor System with Multi-Objective Optimization Designed SFD

2019 ◽  
Vol 9 (17) ◽  
pp. 3628 ◽  
Author(s):  
Liang Ma ◽  
Jun Wang ◽  
Guichang Zhang
Keyword(s):  
Fundamental Frequency ◽  
Working Conditions ◽  
Optimization Method ◽  
Rotor System ◽  
Dynamic Responses ◽  
Multi Objective Optimization ◽  
Operational Parameters ◽  
Multi Objective ◽  
Coupling Fault ◽  
Misalignment Fault

As an important part of the turbomachinery, the rotor–bearing system has been upgraded to provide a high rotating speed in order to meet the demand of high power production. With increasing demand for stability, the squeeze film damper (SFD) has been widely used in industrial machinery because it can reduce the vibration amplitude and suppress the external force. Usually, it shows inadaptability under the different working conditions where the SFD parameters didn’t change appropriately. Therefore, the reasonable choice of operational parameters of SFD is the key solution that can provide viscous damping effectively and restrain the nonlinear vibration generated by faults. In this paper, the mathematical model of a rotor-ball bearing-SFD system considering the misalignment fault and misalignment-rubbing coupling fault is built first. Then the dynamic characteristics under typical working conditions (ω = 1000 rad/s) of the faulted rotor are discussed. The vibration attenuation effects of the SFD parameters selected by using the multi-objective optimization method on the dynamic responses are analyzed. The results show that when the rotor system operates under different states, the value and the sensitivity of optimization parameters are altered. With no fault, the amplitude of fundamental frequency decrease 23%. With the misalignment fault, the amplitude of the fundamental frequency decreases by 43.4%, the amplitude of 2× fundamental frequency decreases by 27.5%, and the amplitude of 3× fundamental frequency decreases by 66.7%. With the misalignment-rubbing coupling fault, the amplitude of fundamental frequency reduces by 7.4%, the amplitude of 2× fundamental frequency drops by 51.5%, and the amplitude of 3× fundamental frequency drops by 16.8%. Overall, the feasibility of the optimization method of the variable-structured SFD operational parameters for the faulted rotor system is verified. These parametric analyses are very helpful in the development of a high-speed rotor system and provide a theoretical reference for the vibration control and optimal design of rotating machinery.

scholarly journals Analysis on Influences of Squeeze Film Damper on Vibrations of Rotor System in Aeroengine

2022 ◽  
Vol 12 (2) ◽  
pp. 615
Author(s):  
Haobo Wang ◽  
Yulai Zhao ◽  
Zhong Luo ◽  
Qingkai Han
Keyword(s):  
High Speed ◽  
Vibration Suppression ◽  
Rotor System ◽  
Operating Conditions ◽  
Squeeze Film ◽  
Lumped Mass ◽  
Squeeze Film Damper ◽  
Rotor Systems ◽  
Vibration Responses ◽  
Stiffness And Damping

Squeeze film damper (SFD) is widely used in the vibration suppression of aeroengine rotor systems, but will cause complex motions of the rotor system under specific operating conditions. In this paper, a lumped-mass dynamic model of the high-pressure rotor system in an aeroengine is established, and the nonlinear stiffness and damping formula of SFD are introduced into the above model. The vibration responses of the rotor system under different rotating speeds and with different unbalances are investigated numerically, and the influence of SFD on the rotor system vibration and the change of suppression ability are compared and analyzed. The results show that in the case of high speed, together with a small unbalance, the rotor system will perform a complex vibration or a bistable vibration due to SFD. If the unbalance is properly increased under the same case of high speed, the vibration of the rotor becomes single-harmonic and the bistable vibration disappears. The research results can provide a helpful reference for analyzing complex vibration mechanisms of the rotor system with SFD and achieving an effective vibration suppression through unbalance regulation.

scholarly journals Dynamics of Flexible Rotor Systems with an Interim Mass Unbalanced Disk Using a Spectral Element Model

2014 ◽  
Vol 2014 ◽  
pp. 1-14
Author(s):  
Sangkyu Choi ◽  
Usik Lee
Keyword(s):  
Natural Frequencies ◽  
Equations Of Motion ◽  
Element Model ◽  
Spectral Element ◽  
Rotor System ◽  
Dynamic Responses ◽  
Disk System ◽  
Unbalanced Mass ◽  
Rotor Systems ◽  
Blade System

A frequency domain spectral element model is developed for a rotor system that consists of two spinning shafts and an interim disk or blade system. In this study, the shafts are represented by spinning Timoshenko beam models, and the interim disk system is represented by a uniform thick rigid disk with an unbalanced mass. In our derivation of the governing equations of motion of the disk system, the disk is considered to be wobbling about the geometric center of the disk at which the spinning shafts are attached. The high accuracy of the proposed spectral element model is evaluated by comparison with the natural frequencies obtained using the conventional finite element method (FEM). The spectral element model is then used to investigate the effects of the unbalanced mass on the natural frequencies and dynamic responses of an example rotor system.

Dynamics of High-Speed Cam-Driven Mechanisms—Part 2: Nonlinear System Models

1975 ◽  
Vol 97 (3) ◽  
pp. 777-781 ◽  
Author(s):  
F. Y. Chen ◽  
N. Polvanich
Keyword(s):  
Nonlinear System ◽  
High Speed ◽  
Phase Plane ◽  
Response Spectra ◽  
Equation Of Motion ◽  
Dynamic Responses ◽  
System Model ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Shock Response

The dynamic responses of the cam-driven mechanism are investigated, based on a non-linear lumped system model. The nonlinearity is an energy-dissipating element which consists of viscous, quadratic, Coulomb and static frictions combined. The nonlinear equation of motion of a single degree of freedom is first analyzed using a numerical method and the results of time responses are presented and characterized in the phase-plane. The primary and residual shock response spectra in nondimensional form for a number of typical cam input excitations are presented and compared with those of the associated linear cases.

Effect of the inlet oil temperature on vibration characteristics of the high-speed turbocharger rotor system

2021 ◽  
pp. 135065012098703
Author(s):  
Xinli Zhong ◽  
Yuan Huang ◽  
Guangfu Bin ◽  
Anhua Chen
Keyword(s):  
Finite Element ◽  
Power Consumption ◽  
Finite Element Model ◽  
Temperature Rise ◽  
High Speed ◽  
Element Model ◽  
Rotor System ◽  
Speed Ratio ◽  
Oil Film ◽  
Light Load

The inlet oil temperature of the rotor system with high-speed and light-load turbocharger will change during operation, which will change the vibration characteristics of the rotor system and even cause vibration accidents. Taking a certain type of high-speed and light-load turbocharger rotor system as the research object, the changes in oil film viscosity, friction power consumption, oil film temperature rise, and ring speed ratio with the inlet oil temperature of floating ring bearings are analyzed. A dynamic finite-element model of the turbocharger rotor–floating-ring-bearing system is constructed, and the finite-element model is verified through the critical speed and colormap spectrogram. The Newmark integral method is used to analyze the nonlinear transient response of the rotor system, and the influence of the inlet oil temperature on the vibration response characteristics of the rotor system is studied. The results show that an increase in the inlet oil temperature leads to a decrease in the internal and external oil film viscosities, frictional power consumption, temperature rise, and an increase in the ring speed ratio. When the inlet oil temperature increases from 50 °C to 130 °C, the amplitude of the inner oil film oscillation will gradually decrease, but the amplitude of the outer oil film vortex will gradually increase, and the journal speed point where the inner oil film oscillation and the outer oil film vortex will appear about 30% in advance. In summary, the rotor vibration is better when the inlet oil temperature is about 90 °C. The conclusion of this paper can provide a theoretical reference for selecting the operating parameters of the rotor system with the least vibration for high-speed light-load turbochargers.

Turbocharger rotor vibration reduction methodology with an active control scheme

2021 ◽  
pp. 095745652110307
Author(s):  
Rajasekhara Reddy Mutra ◽  
J Srinivas ◽  
Jakeer Hussain Shaik ◽  
Maddela Chinna Obaiah ◽  
Gunji Balamurali ◽  
...  
Keyword(s):  
High Speed ◽  
Active Vibration Control ◽  
Vibration Reduction ◽  
Open Loop ◽  
Rotor System ◽  
Dynamic Responses ◽  
Experimental Result ◽  
Loop Control ◽  
Highly Nonlinear ◽  
Control Configuration

The turbocharger rotors are often supported on the dual film floating ring bearings that are meant for high-speed applications. The damping ability of these bearings is relatively high. However, due to highly nonlinear bearing forces, often system instability occurs. The present work focuses on the dynamic analysis and active vibration control studies of a practical turbocharger rotor system with the use electromagnetic actuator (EMA) system. Initially, the system is analyzed using the finite element approach. The inner and outer film forces are considered along with rotor imbalance forces. The dynamic responses at the critical operating speeds are obtained numerically. To minimize the vibration amplitudes, a tiny EMA system is installed at one of the nodes along the shaft. The effect of the EMA parameters such as the number of turns of winding coil around a pole ( N c) and pole-face area ( A a) on the response of the system is studied. Further, an open-loop control configuration is practically studied by using a vibration shaker at the bearing node under different operating speeds, and the percentage reduction in critical vibration amplitudes is recorded. The EMA system is effectively controlling the high-speed rotor system vibrations. The EMA parameters N c and A a are influencing the system vibration response. Further, an experimental result has given considerable vibration reduction with the present approach.

Investigation on the Excitation Characteristics and Dynamic Response of the Multi-Support Flexible Rotor With Misalignment

2017 ◽  
Author(s):  
Sen Xiao ◽  
FaYong Wu ◽  
YanHong Ma ◽  
Jie Hong
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Structural Characteristics ◽  
Rotation Frequency ◽  
Frequency Component ◽  
Typical Feature ◽  
Rotor System ◽  
Flexible Rotor ◽  
Rotor Systems ◽  
Response Characteristics

Aiming at the misaligned problems of high-speed flexible multi-supported rotor system, considering the structural characteristics and load characteristics of the rotor, the unbalanced excitation of the rotor with misalignment is presented and quantitatively described. The mechanical model of the high-speed flexible rotor system with multi-support under misaligned excitation is established. Based on the finite element method, the dynamic equation of the rotor system is given and the dynamic response characteristics of rotor systems are studied. The results show that the misalignment for the highspeed multi-support flexible rotor system can not only lead to 2X excitation and support stiffness nonlinearity, but also bring additional unbalanced excitation to the rotor system. The 2X frequency component is one typical feature for the rotor system with bearing misalignment. The vibration response of the rotor showed a trend of “increased slowly first, then reduced quickly as the rotation frequency increased”, and it turns to be more obvious with the increasing of the nonlinear stiffness and unbalance.

Fault Diagnosis of Wind Turbine Gearboxes

2012 ◽  
Vol 512-515 ◽  
pp. 715-718
Author(s):  
Yu Bai Zhang ◽  
Hui Qun Yuan ◽  
Yin Xin Yu ◽  
Hai Jiang Kou ◽  
Ming Xuan Liang
Keyword(s):  
Wind Turbine ◽  
High Speed ◽  
Fault Location ◽  
Natural Frequencies ◽  
Experimental Tests ◽  
Element Model ◽  
Frequency Domain Analysis ◽  
Mode Shapes ◽  
Frequency Components ◽  
The Finite Element Model

Abnormal vibration appeared when experimental tests was carried out on gearboxes of a 1.5MW wind turbine. In this paper, Time-domain and frequency- domain analysis of test data was implemented based on the method of wavelet denoising, the fault location was determined, and the vibration fault indicators and frequency components were obtained. The finite element model of the gearboxes were established, and the natural frequencies and mode shapes were achieved by calculating. The results showed that the fault occurred in the high speed shaft parts, fault vibration frequency was caused by high-speed shaft eccentric resonance frequency and the frequency generated by the natural frequency and the edge frequency that caused by turning. The research layed the foundation for the study of noise reduction and optimization of the wind turbine gearboxes.

Synchronous Response to Rotor Imbalance Using a Damped Gas Bearing

2009 ◽  
Author(s):  
Bugra H. Ertas ◽  
Massimo Camatti ◽  
Gabriele Mariotti
Keyword(s):  
High Speed ◽  
Experimental Tests ◽  
Rotor System ◽  
Rotor Imbalance ◽  
High Speeds ◽  
Speed Range ◽  
Speed Stability ◽  
Stiffness And Damping ◽  
Gas Bearing ◽  
Large Rotor

One type of test performed for evaluating bearings for application into turbomachinery is the synchronous bearing response to rotor imbalance. This paper presents rotordynamic tests on a rotor system using a 70mm diameter damped gas bearing reaching ultra-high speeds of 50,000 rpm. The main objective of the study was to experimentally evaluate the ability of the damped gas bearing to withstand large rotor excursions and provide adequate damping through critical speed transitions. Two critical speeds were excited through varying amounts and configurations of rotor imbalance, while measuring synchronous rotordynamic response at two different axial locations. The results indicated a well-damped rotor system and demonstrated the ability of the gas bearing to safely withstand rotor vibration levels while subjected to severe imbalance loading. Also, a waterfall plot was used to verify ultra high-speed stability of the rotor system throughout the speed range of the test vehicle. In addition to the experimental tests, a rotordynamic computer model was developed for the rotor-bearing system. Using the amplitude/frequency dependent stiffness and damping coefficients for the ball bearing support and the damped gas-bearing support, a pseudo-nonlinear rotordynamic response to imbalance was performed and compared to the experiments.

scholarly journals Relation Between Track Irregularity of Speed-Increased Railway and Dynamic Speed Limits Through Simulation

2014 ◽  
Vol 8 (1) ◽  
pp. 197-200 ◽  
Author(s):  
Wang Zhi-Chen ◽  
Song Ying ◽  
Wang Jian-Xi
Keyword(s):  
High Speed ◽  
Simulation Software ◽  
Dynamic Responses ◽  
System Model ◽  
Railway Vehicle ◽  
Operation Speed ◽  
Coupling System ◽  
Different Types ◽  
Speed Management ◽  
Track Irregularity

Based on the vehicle-track coupled dynamics theory and the corresponding simulation software ADAMS/Rail software package, a vehicle-track coupling system model is established, and the track irregularity is introduced to the coupling system model as an excitation source. Firstly, the dynamic responses of speed-increased railway vehicle and track components due to different types of track irregularity are obtained. Secondly, the sensitive wavelength of different track irregularities in high-speed operation is discussed. Finally, suggestions about the maximum operation speed to meet the standards value of daily maintenance target, comfortable value, emergency repair and speed management target are put forward.

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