• Title/Summary/Keyword: Shaft vibration

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Characteristics of the Shaft Vibration in a High Head Pump-Turbine (고낙차 펌프-터빈에서의 축계 진동 특성)

  • Ha, Hyun Cheon;Choi, Seong Pil
    • 유체기계공업학회:학술대회논문집
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    • 1998.12a
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    • pp.166-172
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    • 1998
  • This paper describes the shaft vibration phenomena measured on a pump-turbine ofa pumped storage power plant. The pump-turbine runs at a rotational speed of 450 rpm (7.5 Hz). The power output (load) of the pump-turbine was varied from 100 to 300 MW in the generating mode. It was found that the magnitude of the shaft vibration was highly dependent upon the power load. The vibration magnitude of the shaft vibration is very high in the middle load zone from 170 to 210 MW, elsewhere the vibration low. From vibration spectra, it was found that the frequency of major vibration in that load zone was 2.5 Hz which is approximately $34\%$ of the shaft rotating speed in Hz. This frequency component disappeared below and above that load zone. This subsynchronous vibration is caused by the flow induced disturbance due to spiral vortex flow downstream of the pump-turbine runner. Furthermore, it was found that shaft vibration was highly decreased due to the increase of bearing preload.

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Characteristics of the Shaft Vibration in a High Head Pump-Turbine (고낙차 펌프-터빈에서의 축계 진동 특성)

  • Ha, Hyun-Cheon;Choi, Seong-Pil
    • The KSFM Journal of Fluid Machinery
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    • v.2 no.2 s.3
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    • pp.27-31
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    • 1999
  • This paper describes the shaft vibration phenomena measured on a pump-turbine of a pumped storage power plant. The pump-turbine runs at a rotational speed of 450 rpm (7.5 Hz). The power output (load) of the pump-turbine is varied from 100 to 300 MW in the generating mode. The magnitude of the shaft vibration highly depends on the power load. The vibration magnitude of the shaft is very high in the middle load zone from 170 to 210 MW, elsewhere the vibration is low. From nitration spectra, it is shown that the frequency of major nitration in that load zone is 2.5 Hz which is approximately $34\%$ of the shaft rotating speed in Hz. This frequency component does not occur below and above that load zone. This subsynchronous vibration is caused by the flow induced disturbance due to spiral vortex flow downstream of the pump-turbine runner. Furthermore, the shaft vibration is highly decreased due to an increased bearing preload.

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Measurement Errors of Non-contact Type Vibration Sensors Used for Precision Measurement of Shaft Vibration (정밀 축진동 측정에 사용되는 비접촉식 진동센서의 측정오차)

  • 전오성;김동혁;최병천
    • Journal of KSNVE
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    • v.1 no.2
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    • pp.107-113
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    • 1991
  • When non-contact type vibration probes are used for the precision measurement of shaft vibration, they can induce the measurement errors due to the shaft curvature since they have been calibrated for the flat plate. In this study the errors due to the shaft radius and the misalignment between the shaft and probe centerlines are analyzed, and an in-situ calibration tool, which can be conveniently used for calibration independent of the shaft curvature and material, is introduced.

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Vibration Analysis of a Multi-Stage Rotating Shaft Shape (다단 회전축계 형상의 진동 연구)

  • Song, OhSeop;Park, Sangyun;Kang, Sunghwan;Seo, Jungseok;Kim, Sunhong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2013.10a
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    • pp.730-735
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    • 2013
  • This paper contains various vibration analysis of multi-stage shaft shape such as the bending, torsional and axial vibration. The shaft system is modeled as Timoshenko beam with the transverse shear and rotary inertia effect and the equation of motion is derived by Hamilton's principle with considering clamped-free boundary condition. Then, eigenvalue problem of discrete equation of motion for multi-stage shaft model is solved and got results of the natural frequency through the numerical analysis. Obtained numerical analysis results through Matlab program were compared with those of FEM analysis to verify the results. This study suggests that design of shaft system be consider torsional and axial vibration as well as bending vibration.

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The Dynamic Characteristic Test of Oil pump Integrated Balance Shaft Module (오일펌프 내장형 밸런스 샤프트 모듈의 동특성 시험)

  • Seong, Eun-Je;Kang, Dae-Gyu;Jeong, Chan-Yong;Han, Chang-Soo;Kim, Myung-Soo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.403-408
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    • 2007
  • According as diesel automobile are produced, reduce noise and vibration that is occurred by characteristic of diesel engine, and need engine room layout optimization and research for light weight of parts. Balance Shaft Module is module parts for vehicles engine to improve performance and efficiency of engine and reduce noise and vibration. These days, an oil pump integrated balance shaft module and an oil sump integrated balance shaft module is on the rising for optimizing of engine room. In this study, produced prototype of oil pump integrated type balance shaft module, and achieved dynamic characteristic test about experimental modal analysis and noise/vibration of balance shaft module.

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A Study on the Vibration Characteristics of Critical Speed for Rotor Shaft (회전샤프트의 위험속도에 관한 진동특성 연구)

  • Son, Choong-Yul;Lee, Kang-Su;Ryu, Young-Hyun
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.18 no.9
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    • pp.961-971
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    • 2008
  • In the design of a rotor shaft, care should be taken to minimize vibration by taking into account the sources of vibration. In addition, the intensity critical speed, stability, and other related aspects of the system must be considered. especially when it is operated at a critical speed, it is important to address issues related to vibration, as an increase in the whirling response of the rotor shaft can cause damage to the shaft, destruction of the rotor parts, and detrimental abrasions on the bearings. In this thesis, the vibration characteristics of a rotor shaft are investigated through the use of the finite element method. Variations of the diameters and lengths were used to determine the effect of a rotor shaft using Beam No.188(3D linear strain beam) in ANSYS version 11.0 as a universal interpretation program for finite elements. Special care was taken to prevent excessive vibration, which can result from resonance at the initial stage, in the formulation of a dynamic design for a rotor shaft through calculations while changing the diameters and the lengths of the shaft. Moreover, the dynamic characteristics of the critical speed, total mass, D/L(diameter to length) ratio, and natural frequency were verified. Furthermore, the rotor shaft applied by bearing element was calculated and compared by using Combi No. 214(2-D spring-damper bearing).

Influence on the Torsional Vibration of Input Shaft and the Vibration of Vehicle by Damper Clutch in Auto-Transmission (자동변속기의 댐퍼 클러치가 Input Shaft 의 비틀림 진동 및 차체 진동에 미치는 영향 연구)

  • Jung, Byung-Hwan;Hwang, Seon-Yang;Kang, Koo-Tae
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2009.10a
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    • pp.344-350
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    • 2009
  • According to torsional vibration characteristic of a damper clutch in auto-transmission, the input shaft system have occurred breakdown for the duration cycle and over-vibration happened on vehicle at specific condition. This paper describes the improvement of the torsional vibration of input shaft and the vehicle vibration by tuning of the damper clutch and suggests to the guide line about torsion characteristic on the design of damper clutch.

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Resonance and Instability of Blade-Shaft Coupled Bending Vibrations with In-plane Blade Vibration

  • Anegawa, Norihisa;Fujiwara, Hiroyuki;Okabe, Akira;Matsushita, Osami
    • International Journal of Fluid Machinery and Systems
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    • v.1 no.1
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    • pp.169-180
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    • 2008
  • As a major component of a power plant, a turbine generator must have sufficient reliability. Longer blades have lower natural frequency, thereby requiring that the design of the shaft and blade takes into account the coupling of the blade vibration mode, nodal diameter k=0 and k=1 with vibration of the shaft. The present work analyzes the coupling of the translation motion of the shaft with in-plane vibration of the blades with k=1 modes. At a rotational speed ${\Omega}_1=|{\omega}_s-{\omega}_b|$, the resonance of the blades has a relatively large amplitude. A violent coupled resonance was observed at a rotational speed ${\Omega}_2=|{\omega}_s+{\omega}_b|$. Resonance in blade vibration at ${\Omega}_1=|{\omega}_s-{\omega}_b|$ was experimentally confirmed.

The Development of an Automatic Dynamic Inspection System of a Balance Shaft Module (밸런스 샤프트 모듈 자동 동적검사 시스템 개발)

  • Seong, Eun-Je;Kang, Dae-Gyu;Jeong, Chan-Yong;Han, Chang-Soo;Kim, Myung-Soo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.1231-1236
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    • 2007
  • Balance Shaft Module is module parts that is installed to vehicles engine to reduce noise and vibration of vehicles engine. Balance Shaft Module's performance exerts important influence on performance of engine. Therefore, must be able to warrant quality and performance of Balance Shaft Module. Existing product found and revised error at continuous process of production, and estimated failure mode in Balance Shaft Module. Previous method hard to secure product that performance is excellent, and bring a lot of damages economically. Therefore, development of inspectin system for quality inspection of parts and performance test of assembly is essential in Balance Shaft Module. In this study, represented development process of automatic dynamic inspection system to test performance and detect breakdown of Balance Shaft Module that is producing in Dongbo.

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Element Design of Balancing Shaft for Reducing the Vibration in Engine Module (엔진진동 저감을 위한 밸런싱샤프트의 요소설계 기법 연구)

  • Kim, Chan-Jung;Beak, Gyoung-Won;Lee, Bong-Hyun;Kim, Gi-Hoon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.615-620
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    • 2005
  • Vibration in Engine module could be reduced by introducing a balance shaft module which has one or more unbalanced rotors. The unbalanced rotor is unbalanced in one direction that act as a opposite direction of the inertia force or moment triggered by engine component so that the largest order factor in vibration is efficiently decreased The ability of balance shaft to reduce the order element of engine component is investigated by a vehicle testing that is focused on comparing the vibration with balance shaft to that of without balance shaft. One of the commonly adapted balance shaft is tested by modal scheme for indemnifying the dynamic characteristics and an, the modal information is used for a clue to design the balance shaft module. The essential equation deriving the design parameters of unbalanced rotor is also presented for two cases, 3 in-ling and 4 in-ling cylinder model. Finally, the overall design process is explained with flow chart.

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