scholarly journals The Influence of Ring-Speed Ratio Dynamic Change on Nonlinear Vibration Response of High-Speed Turbocharger Rotor System

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Guangfu Bin ◽  
Liang Zhang ◽  
Feng Yang ◽  
Anhua Chen
Keyword(s):  
Nonlinear Vibration ◽  
High Speed ◽  
Dynamic Change ◽  
Element Model ◽  
Rotor System ◽  
Vibration Response ◽  
Speed Ratio ◽  
Model Parameters ◽  
Rotor Vibration ◽  
Nonlinear Transient

The ring-speed ratio is a comprehensive dynamic index of floating ring bearing structure and operating parameters, which directly affects the dynamic behavior of the turbocharger rotor system. The cross stiffness of ring-speed ratio and floating ring bearing and the work of oil film force are analyzed. The influence of dynamic ring-speed ratio change on the vibration response of floating ring bearing was studied. The finite element model of the rotor-floating ring bearing system is constructed; its model parameters are verified through the measured critical rotor speed. Newmark integral method is used to analyze the nonlinear transient response. The results show that when the ring-speed ratio is between 0.18 and 0.24, the rotor is in a good operating state; when it increases from 0.24 to 0.36, the rotor vibration is dominated by frequency division, and the system will be less stable. The square of the ring-speed ratio is inversely proportional to the rotational speed of the journal where the subfrequency vibration occurs. It helps to know the nonlinear vibration by judging the journal speed when the rotor vibration occurs in subfrequency. The conclusion provides a reference for the mechanical dynamics design and intelligent management and maintenance of this kind of turbine rotors.

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.

scholarly journals Nonlinear Vibration Analysis of Rotor considering Cogging and Harmonic Effects

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Shanle Li ◽  
Feng Liu ◽  
Hongyan Wang ◽  
Haijun Song ◽  
Kuilong Yu
Keyword(s):  
Nonlinear Vibration ◽  
Vibration Analysis ◽  
Magnetic Force ◽  
Rotor System ◽  
Kutta Method ◽  
Rotor Vibration ◽  
Motion Equations ◽  
Runge Kutta Method ◽  
Static Eccentricity ◽  
New Formula

This paper aims to investigate nonlinear vibration characteristics of rotor system considering cogging and harmonic effects. Firstly, relative permeance with eccentric was established and then corrected by correction factor caused by the cogging effect. Based on the new formula of relative permeance, the expression of unbalanced magnetic force was obtained, and the coefficient of cogging effect was defined. Motion equations of rotor system were established, and Runge–Kutta method was used to solve the equations. Results showed that errors between finite and analytical results were smaller considering cogging and harmonic effects. When the harmonics were taken into consideration, the vibration of rotor increases sharply. When the cogging and harmonics were taken into consideration simultaneously, the vibration of rotor decreased instead, which means that stator slots have the effect of reducing vibration in rotor system. Rotor vibration was axis symmetry with static eccentricity rather than central symmetry with no eccentricity, and double, four times, and six times supply frequency always existed in the components of main frequency with eccentric.

Effects of High-Speed Railway in Tunnel on Vibration Response of Upper Building

2013 ◽  
Vol 482 ◽  
pp. 155-162
Author(s):  
Si Hui Xu ◽  
Xiao Hui Zhang ◽  
Han Chen
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Reaction Force ◽  
Element Model ◽  
Vibration Response ◽  
Vibration Level ◽  
High Speed Railway ◽  
Proper Distance ◽  
Coupling Dynamic ◽  
Coupling Dynamic Model

In order to study the effects of high-speed railway in tunnel on vibration response of upper building, the Vehicle-Track-Tunnel-Soil-Building coupling dynamic model was established, and the reaction force of fasteners was used to transmit between Vehicle-Track coupling dynamic model and Tunnel-Soil-Building finite element model. According to modal analysis for typical section of building, sensitive frequency range and sensitive structure locations were obtained. In terms of two conditions, Tunnel-Building Integrated Structure and building are evaded from tunnel for some distance, 1/3 octave vibration level and VLZ vibration acceleration level for all measuring points were calculated to analyze the vibration response of building. The results are shown as follows: for Tunnel-Building Integrated Structure, the overall vibration level is high,which is above 65dB. 2-3dB will be reduced by decreasing speed and improving standard of track. when building is evaded from tunnel for some distance, with larger evaded distance, the vibration response is slighter. However, when evaded distance is above 30m, vibration may be amplified ,so its necessary to select proper distance. Vibration response of structure is most strong when 4 lines meet under building, so strict limitation on meeting condition of trains can effectively reduce vibration level.

scholarly journals Dynamic Characteristics and Experimental Research of Dual-Rotor System with Rub-Impact Fault

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Hongzhi Xu ◽  
Nanfei Wang ◽  
Dongxiang Jiang ◽  
Te Han ◽  
Dewang Li
Keyword(s):  
Dynamic Characteristics ◽  
Element Model ◽  
Rotor System ◽  
Rotor Vibration ◽  
Double Frequency ◽  
Fundamental Frequencies ◽  
Outer Rotor ◽  
Dimensional Finite Element ◽  
Frequency Components ◽  
Collision Force

Rub-impact fault model for dual-rotor system was further developed, in which rubbing board is regarded as elastic sheet. Sheet elastic deformation, contact penetration, and elastic damping support during rubbing of sheet and wheel disk were considered. Collision force and friction were calculated by utilizing Hertz contact theory and Coulomb model and introducing nonlinear spring damping model and friction coefficient. Then kinetic differential equations of rub-impact under dry rubbing condition were established. Based on one-dimensional finite element model of dual-rotor system, dynamic transient response of overall structure under rub-impact existing between rotor wheel and sheet was obtained. Meanwhile, fault dynamic characteristics and impact of rubbing clearance on rotor vibration were analyzed. The results show that, during the process of rub-impact, the spectrums of rotor vibration are complicated and multiple combined frequency components of inner and outer rotor fundamental frequencies are typical characteristic of rub-impact fault for dual-rotor system. It also can be seen from rotor vibration response that the rubbing rotor’s fundamental frequency is modulated by normal rotor double frequency.

scholarly journals Vibration Response Characteristics of the Cross Tunnel Structure

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Jinxing Lai ◽  
Kaiyun Wang ◽  
Junling Qiu ◽  
Fangyuan Niu ◽  
Junbao Wang ◽  
...  
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Time History ◽  
Element Model ◽  
Vibration Response ◽  
Shield Tunnel ◽  
Tunnel Structure ◽  
Response Characteristics ◽  
Vehicle Load ◽  
Metro Tunnel

It is well known that the tunnel structure will lose its function under the long-term repeated function of the vibration effect. A prime example is the Xi’an cross tunnel structure (CTS) of Metro Line 2 and the Yongningmen tunnel, where the vibration response of the tunnel vehicle load and metro train load to the structure of shield tunnel was analyzed by applying the three-dimensional (3D) dynamic finite element model. The effect of the train running was simulated by applying the time-history curves of vibration force of the track induced by wheel axles, using the fitted formulas for vehicle and train vibration load. The characteristics and the spreading rules of vibration response of metro tunnel structure were researched from the perspectives of acceleration, velocity, displacement, and stress. It was found that vehicle load only affects the metro tunnel within 14 m from the centre, and the influence decreases gradually from vault to spandrel, haunch, and springing. The high-speed driving effect of the train can be divided into the close period, the rising period, the stable period, the declining period, and the leaving period. The stress at haunch should be carefully considered. The research results presented for this case study provide theoretical support for the safety of vibration response of Metro Line 2 structure.

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 Nonlinear Dynamic Behavior of Double-Disk Isotropic Rotor System with Axial Rub-Impact

2011 ◽  
Vol 2-3 ◽  
pp. 678-682
Author(s):  
Y. Zhang ◽  
W.M. Wang ◽  
J.F. Yao
Keyword(s):  
Dynamic Behavior ◽  
Nonlinear Dynamic ◽  
High Speed ◽  
Element Model ◽  
Rotor System ◽  
Self Healing ◽  
Rotor Bearing ◽  
Nonlinear Dynamic Behavior ◽  
Operation Stability ◽  
Bearing System

In the case of considering the shear effect and gyroscopic effect, a finite element model is developed to study the nonlinear dynamic behavior of a double-disk isotropic rotor- bearing system with axial rub-impact in this paper. The influences of rotational speed and initial phase difference on the operation stability of the rotor-bearing system are discussed. It transpires that the response of the rotor system with axial rub- impact is mainly synchronous periodic motion. The vibration signals of axial rub-impact include such as the synchronous signal and the multiple frequencies, in which the synchronous signal is dominating signal. There is no weakening wave phenomenon in time wave plot. All the results are in reasonable good agreement with those observed in engineering. The results of this paper could provide certain reference for fault diagnosis and self-healing of large high-speed rotating machinery system, thus ensuring the safe operation of the system.

Development of a Computational Model to Visualize Air Flow Into Surrogate Ballistic Wounds

2017 ◽  
Author(s):  
John Ziadat ◽  
Karim H. Muci-Küchler
Keyword(s):  
Spatial Data ◽  
High Speed ◽  
Bacterial Contamination ◽  
Air Flow ◽  
Mechanical Damage ◽  
Element Model ◽  
Model Parameters ◽  
Pressure Dynamics ◽  
Time Histories ◽  
Solid Bodies

In addition to the direct mechanical damage that takes place during a ballistic injury, the formation of the temporary wound cavity creates a suction effect capable of introducing debris, particles, and bacteria from the environment into the wound track. This introduction of bacterial contamination into the wound can give rise to infections which may delay healing or result in more serious problems. Various authors have conducted controlled ballistics experiments placing bacterial contamination on the surface of ballistics gelatin targets to study the effect of parameters such as projectile caliber and speed on the distribution of bacteria along the permanent cavity. The results reported in the literature showed that bacteria were present along the entire surrogate wound track. Understanding the contribution that the formation of the temporary cavity has on the number and distribution of bacteria along the surrogate wound requires the development of experiments to visualize the flow of air during the transient phase of target deformation and the use of numerical simulations to predict variables associated with the flow of air, like pressure-time histories along the projectile path, that cannot be directly measured during experiments. This paper discusses the development of a finite element model using ANSYS Autodyn for the simulation of a small caliber projectile traveling at moderate speeds penetrating a soft tissue surrogate target made of ballistics gelatin. The model uses a Coupled Eulerian-Lagrangian formulation and discretization scheme, which allows for the analysis of not only the deformation of the solid bodies, but also of the flow of air into the wound track. For model validation, the numerical results are compared to spatial data extracted from high speed video recorded during experiments matching key model parameters. Comparisons of the numerical and experimental results indicate that the model is providing reasonable results for the deformations and overall air flow. The predicted pressure dynamics within the simulated wound track clearly suggest that areas of partial vacuum exist within the cavity, which is consistent with the suction effect mentioned by several researchers.

scholarly journals Finite Element Modeling and Vibration Analysis of Sprag Clutch-Flexible Rotor System

2020 ◽  
Author(s):  
chuang huang ◽  
yongqiang zhao ◽  
guanghu jin
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
High Speed ◽  
Element Model ◽  
Vibration Characteristics ◽  
Rotor System ◽  
Operating Conditions ◽  
Resonant Peak ◽  
Flexible Rotor ◽  
Calculation Results

Abstract To study the overall vibration characteristics of the sprag clutch-flexible rotor system (SC-FRS) under high-speed operating conditions, a finite element model of SC-FRS considering rotor flexibility and bearing support stiffness is established based on the proposed calculation method of the stiffness matrix. According to this model, the natural frequency and mode shape of the system are calculated, and the correctness of the model is verified by comparing it with the calculation results of ANSYS software. Under the action of unbalance, the bending-torsion coupled vibration and the dynamic load of the inter-shaft bearings are analyzed, and it is found that the resonant peak in the torsional direction has the same resonance frequency as that in the bending direction. A test rig for the sprag clutch-rotor system is built, and the axis trajectory and critical speed are tested. The test results show that the finite element model of SC-FRS can accurately describe the vibration characteristics of the system.

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