Coupling analysis of tribological and dynamical behavior for a thermal turbulent fluid lubricated floating ring bearing-rotor system at ultra-high speeds

2021 ◽  
pp. 107325
Author(s):  
Yi Zhang ◽  
Wei Wang ◽  
Daogao Wei ◽  
Gang Wang ◽  
Jimin Xu ◽  
...  
Keyword(s):  
Dynamical Behavior ◽  
Rotor System ◽  
Coupling Analysis ◽  
Turbulent Fluid ◽  
High Speeds

Optimization of Complex Dynamic Systems With Respect to Their Behavior in Time and Frequency Domain

2011 ◽  
Author(s):  
Matthias Marx ◽  
Chunsheng Wei ◽  
Dirk So¨ffker
Keyword(s):  
Frequency Domain ◽  
Dynamic Systems ◽  
Power Flow ◽  
Dynamical Behavior ◽  
Magnetic Bearing ◽  
Rotor System ◽  
Active Magnetic Bearing ◽  
Design Parameters ◽  
Powertrain System ◽  
Aging Mechanisms

This paper describes an integrated optimization process of dynamic systems including design parameters and control algorithms. In contrast to known approaches the developed approach is based on an optimization loop including the evaluation of the dynamical behavior of technical systems with respect to the behavior and related properties in time and frequency domain. This includes as well the behavior of the system, the objective function as the formulation of the restrictions to be considered for the dynamical behavior (stationary and instationary). The proposed approach is declared in detail and will be illustrated using two typical technical applications as examples. The first application example is the optimization of the control system of an active magnetic bearing (AMB) rotor system. Hereby the modeling of the AMB rotor system is briefly introduced. An H∞ controller is designed for the control of the system. The performance both in time and frequency domain is optimized in parallel. The algorithm will be explained by simulation examples. The second example is the optimization of the pow-ermanagement system of a fuel cell/supercap-based hybrid electric powertrain. Hereby the modeling of the electric power flow within the powertrain system is demonstrated and its influence on certain system properties like availability, efficiency, and typical aging mechanisms is discussed. The proposed method leads to near-optimal results in a few steps for both of the systems introduced.

Electric-Hydraulic Actuator Design for a Hybrid Squeeze-Film Damper-Mounted Rigid Rotor System With Active Control

2005 ◽  
Vol 128 (2) ◽  
pp. 176-183 ◽  
Author(s):  
Her-Terng Yau ◽  
Chieh-Li Chen
Keyword(s):  
Dynamical Behavior ◽  
Rotor System ◽  
Squeeze Film ◽  
Rigid Rotor ◽  
Loop Gain ◽  
Hydraulic Actuator ◽  
Squeeze Film Damper ◽  
Chaotic Vibration ◽  
Squeeze Film Dampers ◽  
Actuator Design

When a squeeze-film damper-mounted rigid rotor system is operated eccentrically, the nonlinear forces are no longer radially symmetric and a disordered dynamical behavior (i.e., quasi-periodic and chaotic vibration) will occur. To suppress the undesired vibration characteristics, the hybrid squeeze-film damper bearing consisting of hydrostatic chambers and hydrodynamic ranges is proposed. In order to change the pressure in hydrostatic chambers, two pairs of electric-hydraulic orifices are used in this paper. The dynamic model of the system is established with the consideration of the electric-hydraulic actuator. The complex nonsynchronous vibration of squeeze-film dampers rotor-bearing system is demonstrated to be stabilized by such electric-hydraulic orifices actuators with proportional-plus-derivative (PD) controllers. Numerical results show that the nonchaotic operation range of the system will be increased by tuning the control loop gain.

Two-Way Coupling Fluid–Structure Interaction Analysis and Tests of Shaft Vibration and Clearance Flow Across Plain Annular Seal

2019 ◽  
Vol 86 (10) ◽  
Author(s):  
Kenjiro Miyake ◽  
Tsuyoshi Inoue ◽  
Yusuke Watanabe
Keyword(s):  
Continuity Equation ◽  
Fluid Structure Interaction ◽  
Rotor System ◽  
Design Stage ◽  
Coupling Analysis ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Annular Seal ◽  
Clearance Flow ◽  
Shaft Vibration

Shaft vibration caused by rotor dynamic (RD) fluid force generated by the seal clearance flow has caused several problems. Because such vibration is a coupled phenomenon of clearance flow and shaft vibration, a coupling analysis is essential to solve these problems. In this study, a two-way coupling fluid–structure interaction (FSI) analysis of the seal clearance flow and shaft vibration of a rotor system was conducted and verified through experiments. The rotor system used was a vertical, flexible rotor system with a plain annular seal. In the numerical analysis of the seal clearance flow, the continuity equation and momentum equations, which were averaged across the film thickness, were numerically solved. To suppress the numerical instability, which is unique to the coupling analysis, and improve its numerical stability, a method of successively correcting pressure and shaft acceleration values was adopted so that the continuity equation and rotor equations of motion could be satisfied at every time step. By performing the coupling simulation, the frequency response characteristics of whirling amplitude and leakage flow were investigated. In regard to the stability of the system, the rotational speeds at which self-excited vibration occurs (onset speed of instability: OSI) in its increasing condition and ceases (onset speed of dropdown: OSD) in its decreasing condition were investigated. The coupling analysis results reasonably agree with the experimental results, which demonstrate the validity of the analysis method. In addition, the influence of static eccentricity and whirling amplitude on stability (OSI and OSD) was clarified, which are useful in the design stage of turbomachinery.

Research on Multi-Disciplinary Behavior Coupling Model in IC Engine

2010 ◽  
Vol 44-47 ◽  
pp. 2075-2079
Author(s):  
Xu Dong Dai ◽  
Zheng Shan Zhang ◽  
Xiang Hui Meng ◽  
Zhi Nan Zhang ◽  
You Bai Xie
Keyword(s):  
Coupling Effect ◽  
Dynamical Behavior ◽  
Cylinder Liner ◽  
Coupling Model ◽  
State Equation ◽  
The State ◽  
Analysis Model ◽  
Coupling Analysis ◽  
Ic Engine ◽  
Cylinder Piston

The paper analyzes the coupling of multi-disciplinary behaviors, including system dynamical behavior, combustion behavior and tribological behavior, of the cylinder liner-piston-rod-crank system in IC engine. Based on the state equation method, multi-disciplinary behavior coupling model of the Cylinder-Piston-Rod-Crank system is constructed and a multi-disciplinary behavior coupling analysis method in IC engine is presented on the basis of the state equation. With the coupling analysis model, the coupling effect of multi-disciplinary behaviors can be considered in the two sequential state calculations. By means of state calculation in time domain, the coupling effect of multi-disciplinary behaviors on life performance of IC engine can be predicted.

Experimental Investigation into the Instability of an Over-Hung Rigid Centrifuge Rotor Partially Filled With Fluid

2002 ◽  
Vol 124 (4) ◽  
pp. 483-491 ◽  
Author(s):  
Zhu Changsheng
Keyword(s):  
Experimental Investigation ◽  
Free Surface ◽  
Upper Bound ◽  
Dynamical Behavior ◽  
Rotor System ◽  
Unstable Region ◽  
Fill Ratio ◽  
Rotor Imbalance ◽  
New Phenomena ◽  
Centrifuge Rotor

The objective of this paper is to experimentally investigate the instability of an over-hung rigid centrifuge rotor partially filled with fluid. Specific emphasis has been placed on the developing process of rotor instability, the dynamical behavior of the rotor system while the instability occurs, and the frequency and direction of rotor whirl within the unstable region of rotational speeds. The effects of fluid-fill ratio on the rotor whirl frequency, the extent of the unstable region of rotational speeds, and the rotor imbalance are also studied. The detailed results clarify some issues and show some new phenomena on the instability of a rotor partially filled with fluid. The phenomena include: sub-synchronous frequency that does not result in instability of the rotor system and disappears in the unstable region at the larger fluid-fill ratios; different whirl frequencies entering the unstable region for slowly increasing and decreasing rotational speed operations; variable whirl frequency within the unstable region; hysteresis at the upper bound of the unstable region; and a break-down of the fluid free-surface.

Paper 7: Design of a Range of Condensing Steam Turbines for the Petrochemical Industry

1968 ◽  
Vol 183 (15) ◽  
pp. 47-55
Author(s):  
D. Whitehouse ◽  
A. J. A. Schoenmakers ◽  
T. J. Goldsmith
Keyword(s):  
Petrochemical Industry ◽  
Rotor System ◽  
Steam Turbines ◽  
High Speeds

To meet the requirements of the industry for condensing turbines capable of high speeds, the turbines need to be specifically designed for the purpose. The authors deal with straight condensing turbines, and show the powers, speeds, and steam conditions which are required. A range of turbines is set down covering speeds up to 20 000 rev/min and powers up to 15 000 hp. A 12 000 rev/min turbine is illustrated, and some design aspects are discussed in more detail. Particular reference is made to the design of the h.p. and l.p. blading, the rotor system, and the governor system.

scholarly journals A Study of the Influence of Rubbing on the Dynamics of a Flexible Disk Rotor System

1993 ◽  
Author(s):  
Fangsheng Wu ◽  
George T. Flowers
Keyword(s):  
Harmonic Balance ◽  
Dynamical Behavior ◽  
Harmonic Balance Method ◽  
Rotor System ◽  
Governing Equations ◽  
System A ◽  
Jeffcott Rotor ◽  
Inertial Moment ◽  
Flexible Disk ◽  
Rotor Model

This study is concerned with investigating the influence of lateral disk flexibility on the dynamics of a rotor system experiencing rub. A rotating, flexible continuous disk/shaft model was developed and the dynamical behavior of this system with and without rubbing was studied. The model developed in this study is similar to the Jeffcott rotor model except that the disk is treated as a laterally flexible continuous circular plate. The motion of the disk was transformed from physical coordinates to a set of generalized coordinates under which the generalized motion was uncoupled and the responses were calculated. Then the inertial moment acting on the shaft was computed and introduced into the governing equations of the shaft motion. Direct integration and the harmonic balance method were used to study the steady state motion of the system. A number of parameter variation studies were performed for varied rub clearances and disk mass influence ratios. The system responses to the rub, its occurrence and development, and the global stability of the observed responses were studied. The results show that rub can be classified into two types: light rub and heavy rub, and the light rub has the forms of forward, backward, or mixed whirling motion. The results also show that the disk flexibility may alter the critical speed to some degree and may also significantly affect the amplitude and stability of the rotor vibration.

Influence of Fluid Film Boundary Migration on Dynamic Coefficients of Journal Bearings and Behavior of Rotor System

2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Changmin Chen ◽  
Jianping Jing ◽  
Jiqing Cong ◽  
Zezeng Dai ◽  
Jianhua Cheng
Keyword(s):  
Journal Bearing ◽  
Boundary Migration ◽  
Dynamical Behavior ◽  
Journal Bearings ◽  
Rotor System ◽  
Fluid Film ◽  
Dynamic Coefficients ◽  
Film Boundary ◽  
Rotor Bearing ◽  
Stiffness And Damping

Abstract The position of fluid film in journal bearing will change while the journal moving in bearing, which can be named fluid film boundary migration (FFBM). It is usually ignored in the calculation of linear dynamic coefficients. While, the errors brought by this neglection was not ever investigated in detail. In this paper, the influence of FFBM on bearing dynamic coefficients and rotor system dynamic behaviors are investigated. A new perturbation-based model is proposed to take the FFBM into account by modifying the boundary conditions of governing equations. It is then verified by the experimental results and analytical results from previous research. Furthermore, the effects of FFBM on stiffness and damping in two typical journal bearings are investigated. The result indicates that the FFBM has a significant influence on dynamic coefficients of full circular journal bearing but little impact on journal bearing with axial grooves. Moreover, it affects the stiffness and damping more significantly in the cases of large length-to-diameter ratios or small eccentricity ratios in full circle bearing. Finally, the dynamical behavior of a rotor-bearing system with considering the FFBM is also investigated. The result shows that the FFBM of oil film has remarkable influences on the instability threshold and imbalance responses of the rotor system, which should not be ignored. The conclusions obtained in this research are expected to be helpful for the design of full circular journal bearings or rotor-bearing systems.

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.

Two-way coupled shooting analysis of fluid force in the annular plain seal and vibration of the rotor system

2020 ◽  
pp. 1-20
Author(s):  
Yudai Kunori ◽  
Tsuyoshi Inoue ◽  
Kenjiro Miyake
Keyword(s):  
Transition Region ◽  
Spectral Radius ◽  
Mutual Influence ◽  
Dynamical Behavior ◽  
Great Influence ◽  
Coupled System ◽  
Rotor System ◽  
Experimental Results ◽  
Coupled Analysis ◽  
Fluid Force

Abstract In turbomachinery, the rotor dynamic (RD) fluid force generated in a fluid element, by the interaction between the shaft behavior and the fluid flow, is one of the causes of the shaft behavior and has a great influence on the stability of the turbomachinery. In order to improve the reliability of turbomachinery, it is important to analyze the dynamical behavior considering the mutual influence of the RD fluid force and shaft motion. In this paper, the two-way coupled analysis between the fluid force in the annular plain seal and the vibration of the rotor system was expanded by introducing the shooting method in it. The frequency response was obtained, and onset speed of instability (OSI) was predicted effectively. The influence of parameters on the OSI was investigated and discussed. Then, the numerical results obtained by this two-way coupled shooting analysis was compared with the experimental results and the validity of the analysis was confirmed. The influence of disturbance on the error of predicted OSI was also discussed. The transition region to instability was introduced for the predicted OSI using the spectral radius, and the error between the numerical and experimental results of the OSI was explained. As a result, the two-way coupled shooting analysis can predict the OSI values in various situation of two-way coupled system more effectively than the direct numerical simulation. Also, the robustness of stability for the predicted OSI can be evaluated simultaneously by investigating the spectral radius and defining the transition region to instability appropriately.

Sign in / Sign up

Export Citation Format

Share Document