• Title/Summary/Keyword: Unbalance Response Analysis

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Analysis of Dynamic Characteristics of Water Injection Pump (물 분사 펌프의 동특성 분석)

  • Lee, Jong Myeong;Lee, Jeong Hoon;Ha, Jeong Min;Ahn, Byung Hyun;Kim, Won Cheol;Choi, Byeong Keun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.12
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    • pp.1483-1487
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    • 2013
  • Water injection pump outputs oil with high pressure during this process, seawater is injected into the well to recover the well pressure and maintain high productivity. A water injection pump has high productivity, and therefore, it serves as a key piece of equipment in marine plants. In this light, water injection pumps are being studied widely in industry. In this study, the rotor dynamics is analyzed to determine the natural frequency according to the bearing stiffness and operation speed change. This study aims to establish the pump reliability through critical speed, stability, and unbalance response analysis.

Robust Design of Leaf Spring of a Polygon Mirror Scanner Motor Against Shock (충격에 강인한 폴리곤 미러 스캐너 모터의 판 스프링 설계)

  • Lee, Sang-Wook;Kim, Myung-Gyu;Jung, Kyung-Moon;Jang, Gun-Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.11a
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    • pp.515-520
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    • 2008
  • This paper develops a mite element model of a polygon mirror scanner motor supported by the sintered bearing and flexible supporting structures to analyze the shock response by using the finite element method and the mode superposition method. The validity of the proposed model is verified by comparing the simulated natural frequencies and shock response with the experimental ones. It investigates the displacement and the stress of the most vulnerable component, i.e. a leaf spring due to shock, and it proposes a robust design of leaf spring of a polygon mirror scanner motor against shock.

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FEM/BEM Modeling of the Top Cap of Scroll Compressors for Analysis of Noise Radiation (스크롤 압축기 상부 캡의 방사 소음 해석을 위한 유한 요소/경계 요소 모델링)

  • Ahn, Jae-Hong;Song, Jae-Soo;Kim, Sung-Won
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.06a
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    • pp.346-350
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    • 2000
  • In scroll compressors, there are two major noise sources. Sturctural path: excitation of the compressor housing by unbalance forces and forces generated by compression cycle. Gas cavity path: excitation of top cap by discharge gas pulsation. In this study, in order to analyze the radiated noise generated by the discharge gas pulsation, FEM/BEM model of the top cap is established. Measured pressure of discharge pulsation is introduced in the FEM model as the excitation and vibration response is calculated. Radiated sound pressure is then obtained by BEM method based on this vibration response. Results are compared with the measured data. It is shown that the trend of the noise radiation can be predicted in this approadch.

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Three-Dimensional Rotordynamic Analysis Considering Bearing Support Effects (베어링 지지 효과를 고려한 3 차원 로터동역학 해석)

  • Park, Hyo-Keun;Kim, Dong-Hyun;Kim, Myung-Kuk;Chen, Seung-Bae
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.902-909
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    • 2006
  • In this study, three-dimensional rotordynamic analyses have been conducted using equivalent beam, hybrid and fun three-dimensional models. The Present computational method is based on the general finite element method with rotating gyroscopic effects of a rotor system. General purpose commercial finite element code, SAMCEF which includes practical rotordynamics module with various types of rotor analysis methods and bearing elements is applied. For the purpose of numerical verification, comparison study for a benchmark rotor model with support bearings is performed first. Detailed finite element models based on three different modeling concepts are constructed and then computational analyses are conducted for the realistic and complex three-dimensional rotor system. The results for rotor stability and mass unbalance response are presented and compared with the experimental vibration test conducted in this study.

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Rotordynamic Design of the Micro Gas Turbine Supported by Air Foil Bearings (공기포일베어링에 지지된 마이크로가스터빈의 회전체동역학적 설계)

  • Kim, Young-Cheol;Han, Jung-Wan;Kim, Kyung-Woong;Kim, Soo-Yong
    • 유체기계공업학회:학술대회논문집
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    • 2003.12a
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    • pp.662-667
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    • 2003
  • This paper presents a performance analysis of the 1st generation bump foil journal bearings for the micro gas turbine TG75. Static performances such as load capacity and attitude angle are estimated by using soft elasto-hydrodynamic analysis technique, and dynamic performances such as stiffness and damping coefficients are estimated by perturbation method. Rotordynamic analysis for TG75 is performed by using the bearing analysis results. TG75 rotor has 2 horizontal and vertical directional natural modes due to the bearing stiffness characteristics. TG75 rotor will be stably operated between the 1st bending mode at 33000cpm and the 2nd bending mode at 85500cpm. Unbalance response analysis results satisfy the API vibration criteria.

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Vibration Analysis of a Rotor considering Nonlinear Reaction of Hydrodynamic Bearing

  • Lee, Soo-Mok;Lim, Do-Hyeong;Bae, Jong-Gug;Yang, Bo-Suk
    • International Journal of Fluid Machinery and Systems
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    • v.2 no.3
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    • pp.254-259
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    • 2009
  • In this paper it was attempted to treat the hydrodynamic journal bearing as a time-based nonlinear reaction source in each step of rotor rotation in order to observe the bearing effect more realistically and accurately in stead of the conventional method of simple linearized stiffness and damping. Lubrication analysis based on finite element method is employed to calculate the hydrodynamic reaction of bearing and Newmark's method was used to calculate the rotor dynamics in the time domain. Simulation for an industrial electrical motor showed remarkable results with differences compared to those by the conventional method in the dynamic behavior of the rotor.

Dynamic Modeling and Analysis of the Washing Machine System with an Automatic Balancer (자동 밸런서를 갖는 세탁기 시스템의 동력학 모델링 및 해석)

  • Oh, Hyuck-Jin;Lee, U-Sik
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.8 s.227
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    • pp.1212-1220
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    • 2004
  • The structural unbalance mass and laundry are the important sources of the severe vibrations of automatic washing machines. In this paper, a mathematical model is developed for the dynamic analysis of the vertical axis automatic washing machines of pulsator-type. In the model, the rigid body motion of tub assembly is represented by six degrees of freedom and the dynamics of automatic hydraulic balancer is represented by one degree of freedom. The fundamental elastic modes of the tub shell and four suspension bars are also taken into account in the mathematical model, based on analytical and experimental modal analysis results. The 12 degrees of freedom equations of motion are derived by using the Lagrange's equations and the present dynamic model is evaluated by comparing the numerical simulation results with experimentally measured data.

Vibration Analysis of Steam Turbine-Generator Rotor System Using Component Mode Synthesis Method (구분모드합성법을 이용한 증기터빈$\cdot$발전기축계의 진동해석)

  • Yang, B.S.;Kim, Y.H.;Choi, B.G.;Lee, H.
    • Journal of KSNVE
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    • v.9 no.2
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    • pp.401-408
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    • 1999
  • A method is presented for the vibration analysis of steam turbine-generator rotor system based on the component mode synthesis method. The motion of each component of the system is described by superposing constraint mode associated with boundary coordinates and constrained normal modes associated with internal coordinates. This method using real fixed-interface modes allows for significant reduction in system model size while retaining the essential dynamic characteristics of the lower modes. The capability of this method is demonstrated in the natural frequency and unbalance response analysis of the steam turbine-generator rotor system in which the dynamics of the pedestal is considered. The results by the present method are compared with finite element method and trnasfer matrix method in terms of the accuracy and computing time.

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Rotordynamic Analysis of a Turbo-Chiller with Varying Gear Loadings Part II : A Driven High-Speed Compressor Pinion-Impeller Rotor-Bearing System (터보 냉동기의 변동 기어하중을 고려한 로터다이나믹 해석 Part II : 피동 고속 압축기 피니언-임펠러 로터-베어링 시스템)

  • 이안성;정진희
    • Journal of KSNVE
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    • v.9 no.5
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    • pp.1042-1049
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    • 1999
  • In the Part I has been reported a rotordynamic analysis of the driving motor-bull gear rotor-bearing system of a turbo-chiller. In this study, Part II, a rotordynamic analysis is performed with the turbo-chiller compressor pinion-impeller rotor system supported on two fluid film bearings. The pinion-impeller rotor system is driven to a rated speed of 14,600 rpm through a speed-increasing pinion-bull gear. It is modeled utilizing the finite element method for analysis. As loadings on the bearings due to the gear action are significant in the system considered, each resultant bearing load is calculated statically by considering the generalized forces of the gear action as well as the rotor itself. The two support bearings, the generalized forces of the gear action as well as the rotor itself. The two support bearings, partial and 3-axial groove bearings, are designed to take their varying loads along with their varying load angles, and they are also analyzed to give their rotordynamic coefficients. Then, a complex rotordynamic analysis of the compressor pinion-impeller rotor-bearing system is carried out to evaluate its stability, whirl natural frequencies and mode shapes, and unbalance responses under various loading conditions. Results show that the bearings and entire rotor system are well designed regardless of operating conditions, i.e., loads and operating speeds.

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The improvement of control strategy in thermal power plant turbine system by nonlinear analysis (비선형성 해석에 의한 화력발전소 터어빈 제어계통에 관한 연구)

  • ;;Hwang, Jae-Ho;Seo, Jin-Hun
    • 제어로봇시스템학회:학술대회논문집
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    • 1989.10a
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    • pp.567-571
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    • 1989
  • This paper describes the improvement of thermal power plant turbine control system by analyzing nonlinear characteristics. The turbine control depends on the frequency variation and boiler condition. The nonlinearity of turbine control is the result of governor/valve properties, steam condition and boiler thermal unbalance. Nonlinear analysis is divided into two; main steam valve position - turbine output anal governor response. Of course, every analysis must be done on considering plant operating condition. In this paper, after analyzing turbine control nonlinearity by numerical method and actual results, the sensitive operating load which corresponds to frequency is proposed, on guarranteed boiler stability. This idea is implemented at Pyung Tack thermal power plant, and the practical results are showed.

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