Efficiency of Balancing by Liquid-Type Automatic Balancing Devices

2014 ◽  
Vol 1040 ◽  
pp. 858-863 ◽  
Author(s):  
Evgeny N. Pashkov ◽  
Nikita Martyushev ◽  
Andrey V. Ponomarev
Keyword(s):  
Vibration Amplitude ◽  
Rotor Speed ◽  
Mathematical Research ◽  
Rotor Vibration ◽  
Liquid Type ◽  
Automatic Balancing ◽  
Rotor Model

The article focuses on modelling the behaviour of a liquid-type automatic balancing device. To perform mathematical research the rotor model is used that contains a ring functioning as a vessel coupled to the rigid shaft being rotatable on bearings. Data on the influence of various factors on balancing accuracy are presented. The obtained modeling results indicate that the vibration amplitude at supercritical frequencies will decrease proportionally to the increase in the parameters of a liquid autobalancer. The performed calculation also reveals that the more the parameters of a liquid autobalancing device, the higher the efficiency of balancing. Provided the condition of the liquid sufficiency in the ring is satisfied, the independence of the rotor vibration amplitude from the mass of the liquid in the vessel is achieved. Critical rotor speed does not depend on the volume of the liquid in the ring if the condition of its sufficiency is met.

Stationary Rotation of the Partially Liquid-Filled Unbalanced Rotor under External Friction Force Action

2014 ◽  
Vol 1040 ◽  
pp. 903-906 ◽  
Author(s):  
E.N. Pashkov ◽  
Nikita Martyushev ◽  
Pavel G. Yurovsky
Keyword(s):  
Rotation Speed ◽  
External Friction ◽  
Design Parameters ◽  
Mathematical Research ◽  
Rotating Shaft ◽  
Critical Rotation ◽  
Unbalanced Rotor ◽  
Liquid Type ◽  
Critical Rotation Speed ◽  
Automatic Balancing

Rotor rotation with liquid layer on the chamber wall under viscoelastic action of the shaft within a planar model is examined in the article. The solution to the problem of determining the deflection of a rotating shaft with liquid filled chamber is given, which is important when designing an automatic balancing device. The issue of the cooperative motion of a solid body and liquid is considered in mathematical research. The set task is performed by applying D'Alembert's principle. The modeling results indicate that an increase in liquid’s mass in a rotor decreases its critical rotation speed; at the same time, the external friction accelerates the system’s self-centering. The developed mathematical models enable us to select the design parameters of a liquid-type autobalancer which operates within the set range of rotor’s angular velocity.

Reduction of Rotor Vibration Amplitude Using PID Tuning Methods

2018 ◽  
pp. 74-88 ◽  
Author(s):  
Leonardo Biagiotti Saint Martin ◽  
Diogo Stuani Alves ◽  
Ricardo Ugliara Mendes ◽  
Katia Lucchesi Cavalca
Keyword(s):  
Vibration Amplitude ◽  
Rotor Vibration ◽  
Pid Tuning ◽  
Tuning Methods

scholarly journals Active Elastic Support/Dry Friction Damper with Piezoelectric Ceramic Actuator

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Liao Mingfu ◽  
Song Mingbo ◽  
Wang Siji
Keyword(s):  
Dry Friction ◽  
Piezoelectric Ceramic ◽  
Vibration Amplitude ◽  
Critical Speed ◽  
Rotor System ◽  
Elastic Support ◽  
Basic Operation ◽  
Friction Damper ◽  
Rotor Vibration ◽  
Active Damper

The basic operation principle of elastic support/dry friction damper in rotor system was introduced and the unbalance response of the rotor with elastic support/dry friction damper was analyzed theoretically. Based on the previous structure using an electromagnet as actuator, an active elastic support/dry friction damper using piezoelectric ceramic actuator was designed and its effectiveness of reducing rotor vibration when rotor traverses its critical speed and blade-out event happened was experimentally verified. The experimental results show that the active elastic support/dry friction damper with piezoelectric ceramic actuator can significantly reduce vibration in rotor system; the vibration amplitude of the rotor in critical speed region decreased more than 2 times, and the active damper can protect the rotor when a blade-out event happened, so the rotor can traverse the critical speed and shut down smoothly. In addition, the structure is much simpler than the previous, the weight was reduced by half and the power consumption was only 5 W.

Optimal Design of Squeeze Film Supports for Flexible Rotors

1983 ◽  
Vol 105 (3) ◽  
pp. 487-494 ◽  
Author(s):  
M. D. Rabinowitz ◽  
E. J. Hahn
Keyword(s):  
Optimal Design ◽  
Vibration Amplitude ◽  
Operating Conditions ◽  
Squeeze Film ◽  
Rotor Vibration ◽  
Design Constraints ◽  
Supply Pressure ◽  
Flexible Rotors ◽  
Wide Range ◽  
Film Lubrication

Assuming central preloading, operation below the second bending critical speed, and full film lubrication, this paper presents a theoretical model which allows one, with minimum computation, to design squeeze film damped rotors under conditions of high unbalance loading. Closed form expressions are derived for the maximum vibration amplitudes pertaining to optimally damped conditions. The resulting vibration amplitude and transmissibility data of design interest are presented for a wide range of practical operating conditions on a single chart. It can be seen that for a given rotor, the lighter the bearing the more easily one can satisfy design constraints relating to allowable rotor vibration levels and lubricant supply pressure requirements. The data presented are shown to be applicable to a wide variety of rotors, and a recommended procedure for optimal design is outlined.

Investigation on Rotor-Labyrinth Seal System with Variable Rotating speed

2019 ◽  
Vol 36 (1) ◽  
pp. 19-29 ◽  
Author(s):  
Xingyun Jia ◽  
Hai Zhang ◽  
Qun Zheng ◽  
Shuangming Fan ◽  
Zhitao Tian
Keyword(s):  
Flow Field ◽  
Vibration Amplitude ◽  
Fluid Dynamic ◽  
Labyrinth Seal ◽  
Leakage Rate ◽  
Time Effect ◽  
Variable Speed ◽  
Rotor Vibration ◽  
Aerodynamic Forces ◽  
Rotating Speed

AbstractThe following paper presents dynamic leakage rate and coupled interaction for variable speed rotor-labyrinth (LABY) seal, with rotating speed from 18 to 30 krpm. Variable speed rotor vibration characteristics are incorporated into transient computational fluid dynamic (CFD) calculations as boundary conditions of seal flow field to show the real-time effect of rotordynamic in seal flow field. Leakage rate across a variable speed rotor-seal increases with rotor vibration, but this effect is prominent at lower speed than at higher speed. Leakage characteristic is determined by differences in rotor vibration amplitude rather than rotating speed. The results also reveal that aerodynamic forces of labyrinth seal flow field can improve rotor stability, and this interaction between rotor and seal decreases with the increase of rotating speed.

Nonsynchronous Vibration of Planar Autobalancer/Rotor System With Asymmetric Bearing Support

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
DaeYi Jung ◽  
Hans DeSmidt
Keyword(s):  
Limit Cycle ◽  
Harmonic Balance ◽  
Nonlinear Behavior ◽  
Rotor System ◽  
Cycle Stability ◽  
Rotor Vibration ◽  
Rotor Systems ◽  
Asymmetric Behavior ◽  
Automatic Balancing ◽  
Comprehensive Study

Due to inherent nonlinearity of the autobalancer, the potential for other, undesirable, nonsynchronous limit-cycle vibration exists. In such undesirable situations, the balancer masses do not reach their desired synchronous balanced steady-state positions resulting in increased rotor vibration. Such behavior has been widely studied and is well understood for rotor systems on idealized bearings with symmetric supports. However, a comprehensive study into this nonlinear behavior of an imbalanced planar-rigid rotor/autobalancing device (ABD) system mounted on a general bearing holding asymmetric damping and stiffness forces including nonconservative effects cross-coupling ones has not been fully conducted. Therefore, this research primarily focuses on the unstable nonsynchronous limit-cycle behavior and the synchronous balancing condition of system under the influence of the general bearing support. Here, solutions for rotor limit-cycle amplitudes and the corresponding whirl speeds are obtained via a harmonic balance approach. Furthermore, the limit-cycle stability is assessed via perturbation and Floquet analysis, and all the possible responses including undesirable coexistence for the bearing parameters and operating speeds have been thoroughly studied. It is found that, due to asymmetric behavior of bearing support, the multiple limit cycles are encountered in the range of supercritical speeds and more complicate coexistences are invited into the ABD–rotor system compared to the case with idealized symmetric bearing supports. The findings in this paper yield important insights for researchers wishing to utilize automatic balancing devices in more practical rotor systems mounted on a asymmetric general bearing support.

Vibration of a Misaligned Rotor System with Asymmetric Shaft Stiffness

2012 ◽  
Vol 503-504 ◽  
pp. 813-818
Author(s):  
Sheng Feng ◽  
Hai Peng Geng ◽  
She Miao Qi ◽  
Lie Yu
Keyword(s):  
Natural Frequency ◽  
Vibration Amplitude ◽  
Rotor System ◽  
Lateral Vibration ◽  
Rotor Speed ◽  
Flexible Coupling ◽  
Parallel Misalignment ◽  
Rigid Disks ◽  
Simulation Results ◽  
Speed Simulation

Vibration characteristics of a misaligned rotor with asymmetric shaft stiffness are studied. The system consists of two shafts connected by a flexible coupling with parallel misalignment, two rigid disks attached at the middle of each shaft and one of the shafts has asymmetric stiffness. The governing ordinary differential equations are derived using Lagrange dynamics and integrated through numerical methods. The effects of asymmetry, eccentricity and misalignment are studied through the peak-to-peak lateral vibration amplitude at different rotor speed. Simulation results show that the amplitude peaks at the natural frequency associated with unbalance and parallel misalignment, while half the natural frequency associated with the asymmetric shaft stiffness. This study may contribute to enrich understanding of the vibration of a rotor system under the cases of eccentricity, parallel misalignment and asymmetric shaft stiffness.

Reducing Lateral Vibration of a Rotor Passing Through Critical Speeds by Phase Modulating

2003 ◽  
Vol 125 (3) ◽  
pp. 766-771 ◽  
Author(s):  
S.-M. Wang ◽  
Q.-S. Lu ◽  
E. H. Twizell
Keyword(s):  
Vibration Amplitude ◽  
Critical Speed ◽  
Lateral Vibration ◽  
Constant Acceleration ◽  
Unbalanced Rotor ◽  
Acceleration Rate ◽  
Modulated Phase ◽  
Response Phase ◽  
Theoretical And Numerical Analysis ◽  
Rotor Model

A method is presented to reduce the lateral vibration amplitude of an unbalanced rotor accelerating or decelerating through its critical speed, by means of modulating the response phase with varying acceleration rate. Theoretical and numerical analysis on the amplitude and the phase characteristics of lateral vibration of a rotor model are made. Numerical results show that when the rotor passes through its critical speed with a modulated phase, the response amplitude can be reduced by 20% or so, compared with the nonmodulated (constant) acceleration case.

scholarly journals Optimal Design of Squeeze Film Supports for Flexible Rotors

1982 ◽  
Author(s):  
M. D. Rabinowitz ◽  
E. J. Hahn
Keyword(s):  
Optimal Design ◽  
Vibration Amplitude ◽  
Operating Conditions ◽  
Squeeze Film ◽  
Rotor Vibration ◽  
Design Constraints ◽  
Supply Pressure ◽  
Flexible Rotors ◽  
Wide Range ◽  
Film Lubrication

Assuming central preloading operation below the second bending critical speed and full film lubrication, this paper presents a theoretical model which allows one, with minimum computation, to design squeeze film damped rotors under conditions of high unbalance loading. Closed form expressions are derived for the maximum vibration amplitudes pertaining to optimally damped conditions. The resulting vibration amplitude and transmissibility data of design interest are presented for a wide range of practical operating conditions on a single chart. It can be seen that for a given rotor, the lighter the bearing the more easily one can satisfy design constraints relating to allowable rotor vibration levels and lubricant supply pressure requirements. The data presented are shown to be applicable to a wide variety of rotors, and a recommended procedure for optimal design is outlined.

Multiple Smart Material Applications Using SMA and MR Fluid Damper for Rotor Vibration Control

2010 ◽  
Author(s):  
T. S. Aravindhan ◽  
K. Gupta
Keyword(s):  
Vibration Control ◽  
Smart Materials ◽  
Resonance Condition ◽  
Mr Damper ◽  
Experimental Results ◽  
Rotor Vibration ◽  
Mr Fluid ◽  
Fluid Damper ◽  
Mr Fluid Damper ◽  
Rotor Model

Application of two smart materials, namely shape memory alloy (SMA) and magnetorheological fluid (MRF) for rotor vibration control is explored to control the synchronous vibration of rotors crossing resonance condition. First a single degree of freedom system is analyzed to study the effect of SMA and MR fluid damper individually, and then the simulations are repeated to find the feasibility of using the two smart materials simultaneously. An MRF damper is designed, fabricated and installed on a rotor system. The fabricated MR damper is tested and an ANFIS model is trained to predict the damper force in the simulations carried out. The experimental rotor model is analyzed using finite element method in Matlab™. Simulations are carried out to study the effect of MR damper on rotor vibration response. Experimental results obtained from the rotor model with the fabricated MRF damper show considerable reduction in peak vertical amplitude as the current in the MR damper coils is increased. A good correlation between the theoretical and experimental results is observed.

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