• Title/Summary/Keyword: Rotor-bearing system

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Effect of Active Control Bearing on Unbalance Response of a Rotor-Bearing System (축-베어링 계의 불균형 응답에 대한 능동 제어 베어링의 효과)

  • 노병후;김경웅
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2001.11a
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    • pp.316-321
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    • 2001
  • The paper presents the unbalance response of a rotor-bearing system supported by an active control bearing. The proportional, derivative and integral controls are employed for the control algorithm of an active control bearing to suppress the unbalance response of a rotor-bearing system. Results of analytical investigations on the unbalance responses of a rotor supported by an active control bearing are presented for various control gains. It is found that the unbalance response of a rotor can be greatly suppressed by the proportional, derivative or integral control of the bearing. The proportional control is more effective than the derivative control at low rotational speed, and the derivative control is more effective than the proportional control at high rotational speed. In the case of the integral control of the bearing , the unbalance response of a rotor is increased as a general rule. However, the integral control of the bearing is extremely superior to proportional or derivative control at very low rotational speed.

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Effect of Active Control Bearing on Unbalance Response of a Rotor-Bearing System (축-베어링 계의 불균형 응답에 대한 능동 제어 베어링의 효과)

  • 노병후;김경웅
    • Tribology and Lubricants
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    • v.18 no.2
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    • pp.99-104
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    • 2002
  • The paper presents the unbalance response of a rotor-bearing system supported by an active control bearing. The proportional, derivative and integral controls are investigated fur the control algorithm of an active control bearing to suppress the unbalance response of a rotor-bearing system. Results of analytical investigations on the unbalance responses of a rotor supported by an active control bearing are presented for various control gains. It is found that the unbalance response of a rotor can be greatly suppressed by the proportional, derivative or integral control of the bearing. The proportional control is more effective than the derivative control at low rotational speed, and the derivative control is more effective than the proportional control at high rotational speed. In the case of the integral control of the bearing, the unbalance response ova rotor is increased as a general rule. However, the integral control of the bearing is extremely superior to proportional or derivative control at very low rotational speed.

Low Noise Design of Rotor-Bearing System (축-베어링계의 저소음 설계)

  • 노병후;김대곤;김경웅
    • Tribology and Lubricants
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    • v.19 no.1
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    • pp.15-20
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    • 2003
  • The purpose of the paper is to investigate the effects of design parameters on the noise of a rotor- bearing system supported in oil lubricated journal bearings. Effects of radial clearance and width of the bearing, lubricant viscosity and mass eccentricity of the rotor are also examined. Numerical results of the parametric studies are summarized through graph for the A-weighted sound pressure level of the bearing with respect to the rotational speed of the rotor. Results show that the sound pressure level of the bearing is markedly influenced by the mass eccentricity of the rotor and the radial clearance and the width of the bearing. The high viscosity of the lubricant slightly decreases the noise of the bearing, but its effect is relatively very low at high speed. The results of the paper could be an aid in the low noise design of rotor-bearing system supported in oil lubricated journal bearings.

Rotordynamic Characteristics of an APU Gas Turbine Rotor-Bearing System Having a Tie Shaft

  • Lee, An-Sung;Lee, Young-Seob
    • Journal of Mechanical Science and Technology
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    • v.15 no.2
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    • pp.152-159
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    • 2001
  • In this paper it is intended to set-up a sound model of the 60,000rpm 100kW prototype APU gas turbine rotor-bearing system, and particularly to investigate the influences of the tie shaft on the rotordynamic characteristics of the entire APU gas turbine rotor-bearing system, employing the dual shaft model. Firstly, a mock-up APU rotor has been constructed to test and verify the model. Analytical natural frequency results have agreed with the corresponding modal test ones to within 5% difference. Then, the rotordynamic characteristics of the prototype APU rotorbearing system have been investigated. Natural vibration and unbalance response analyses results have shown that the inner tie shaft resonance can cause high enough vibration of the outer main rotor shaft. This could be a concern as the rotor journals operate on very thin air film at high speed. It is concluded as a conservative design practice that the inner tie shaft should be explicitly modeled in the rotordynamic analysis of the APU rotor-bearing system.

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Dynamic Response Analysis of a Flexible Rotor During Impact on Backup Bearings (탄성 로터의 백업베어링 충돌 시 동적 응답 해석)

  • Park, K.J.;Bae, Y.C.
    • Journal of Power System Engineering
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    • v.16 no.3
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    • pp.22-28
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    • 2012
  • Active magnetic bearings(AMBs) present a technology which has many advantages compared to traditional bearing concepts. However, they require backup bearings in order to prevent damages in the event of a system failure. In this study, the dynamics of an AMB supported rotor during impact on backup bearings is studied employing a detailed simulation model. The backup bearings are modeled using an accurate ball bearing model, and the model for a flexible rotor system is described using the finite element approach with the component mode synthesis. Not only the influence of the support stiffness, clearance and friction coefficient on the rotor orbit, but also bearing load are compared for various rotor system parameters. Comparing these results it is shown that the optimum backup bearing system can be applicable for a specific rotor system.

Noise and Vibration Characteristics of Externally Pressurized Air proceeding Bearings with a Circular Slot Restrictor (원형 슬롯 레스트릭터를 갖는 외부 가압 공기 저널 베어링의 소음 및 진동 특성)

  • Park, Jung-Koo;Rho, Byoung-Hoo;Kim, Kyung-Woong
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.1277-1282
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    • 2003
  • The purpose of the present paper is to investigate the noise and vibration characteristics of externally pressurized air proceeding bearings with a circular slot restrictor. To do this, the nonlinear transient analysis including rotor imbalance was performed for a rotor-bearing system. The effects of radial clearance and the width of the bearing and mass eccentricity of the rotor on the noise and vibration characteristics of the bearing are also examined. The results show that the noise and vibration of the rotor-bearing system first increase up to critical speed of the system, and then decrease up to instability threshold speed of the system as the rotational speed of the rotor increases, and the noise of the bearing is markedly influenced by the mass eccentricity of the rotor and the radial clearance and the width of the bearing.

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Prediction of Noise and Vibration Characteristics of Externally Pressurized Air Journal Bearings with a Circular Slot Restrictor (원형 슬롯 레스트릭터를 갖는 외부 가압 공기 저널 베어링의 소음 및 진동 특성 예측)

  • Rho, Byoung-Hoo;Park, Jung-Koo;Kim, Kyung-Woong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.6
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    • pp.1028-1033
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    • 2003
  • The purpose of this paper is to investigate the noise and vibration characteristics of externally pressurized air journal bearings with a circular slot restrictor. To do this, the nonlinear transient analysis including rotor imbalance was performed for a rotor-bearing system. The effects of radial clearance and the length of the bearing and mass eccentricity of the rotor on the noise and vibration characteristics of the bearing are also examined. The results show that the noise and vibration of the rotor-bearing system first increase up to critical speed of the system, and then decrease up to instability threshold speed of the system as the rotational speed of the rotor increases, and the noise of the bearing is markedly influenced by the mass eccentricity of the rotor and the radial clearance and the length of the bearing.

A Study on the Vibration Characteristics of Rotor System with Fluid Film Bearing (유막 저어널 베어링이 회전체에 미치는 진동 특성에 관한 연구)

  • Park, Seong-Hwan;O, Taek-Yeol
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.10
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    • pp.37-44
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    • 2002
  • The dynamic behavior of rotor-bearing system has been investigated using finite element method. A procedure is presented for dynamic modeling of rotor-bearing system which consists of shaft elements, rigid disk, flexible bearing and support structure. A finite element model including the effects of rotary inertia, shear deformation, gyroscopic moments is developed. Linear stiffness and damping coefficients are calculated for 2 lobe sleeve bearing. The whirl frequency, mode shape, stability and unbalance response of rotor system including effects of bearing coefficient and support structures are calculated.

Dynamic Analysis of Effect of Number of Balls on Rotor-Bearing System

  • Hwang, Pyung;Nguyen, Van Trang
    • Tribology and Lubricants
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    • v.29 no.4
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    • pp.248-254
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    • 2013
  • This paper presents a numerical model for investigating the structural dynamic response of an unbalanced rotor system supported on deep groove ball bearings. The aim of this work is to develop a numerical model for investigating the effect of the number of balls on the dynamic characteristics of the rotor ball bearing system. The fourth-order Runge-Kutta numerical integration technique has been applied. The results are presented in the form of time displacement responses and frequency spectra. The analysis demonstrates that the model can be used as a tool for predicting the nonlinear dynamic behavior of the rotor ball bearing system under different operating conditions. Moreover, the study may contribute to a further understanding of the nonlinear dynamics of rotor bearing systems.

Dynamic Behavior Analysis of Rotor-Bearing System for Rotary Compressor (로터리 압축기 회전체-베어링계의 동적 거동해석)

  • 김태학
    • Journal of Advanced Marine Engineering and Technology
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    • v.23 no.2
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    • pp.244-251
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    • 1999
  • Large dynamic loads act on the rotor in rotary compressors. There are unbalance forces due to eccentric rotation parts and gas forces induced by the pressure difference between compression and suction gases. Rotor-journal bearing system is nonlinear since the stiffness and damping coef-ficients of the lubrication oil film are not constant in the bearings. in this paper the program for predicting the behaviors of rotor-journal bearing system of rotary compressor is developed. Finite element modeling is used to analyze the flexible rotor. The numerical results are compared with experimental results.

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