• 제목/요약/키워드: Critical Speed Map

검색결과 31건 처리시간 0.019초

API 610 BB5 펌프 개발을 위한 로터다이나믹 특성분석 (Rotordynamic Characteristics Analysis for API 610 BB5 Pump Development)

  • 김병옥;이안성;김성기
    • 한국유체기계학회 논문집
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    • 제14권4호
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    • pp.38-44
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    • 2011
  • This paper deals with the detail rotordynamic analysis for BB5 eight stages pump as development of API 610 BB5 type pump. Dry-run analytical model, not considering operating fluid, and wet-run analytical model, considering operating fluid are established. In addition, plain circular and pressure dam bearings are chosen and it was discussed that each bearing has an effect on dynamic characteristics of pump rotor system. A rotordynamic analysis includes the critical speed map, Campbell diagram, stability, and unbalance response. As results, it was predicted that rated speed of the pump rotor passes through 1st critical speed in dry-run condition regardless of bearings, however, it was verified that, in wet-run condition, the rotor system doesn't have critical speeds even if more than twice rated speed. Hence the resonance problem caused by the critical speeds does not happen since actual operating is in wet-run condition including operating fluid. As a result of unbalance response analysis, the pump rotor has stable vibration response at rated speed, regardless of operating fluid and the proposed bearing types.

은 박막이 코팅된 표면에서 물질전이층의 형성 및 그 트라이볼로지적 역할에 관한 연구 (A Study on the Formation and the Tribological Role of Mass Transfers Layers at Rubbing Silver-coated Surface)

  • 공호성;양승호;윤의성;김대은
    • Tribology and Lubricants
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    • 제18권6호
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    • pp.377-383
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    • 2002
  • The tribological role of mass transfer layer was studied with silver coatings under various ranges of load and sliding speed. Silver coating was performed with a functionally gradient coating method. Tests were per-formed in dry sliding conditions, using a ball-on-disk contact configuration, at the load of 0.0196-17.64 N and the sliding speed of 20-1,000 mm/s in ambient air. Optical microscope and EPMA analyses showed that contact surfaces were covered with the mass transfer layers of agglomerated wear particles depending upon the contact conditions, and they greatly influenced the tribological characteristics of the surfaces. However, the formation of mass transfer layer was suppressed as the sliding speed increased, and above a critical sliding speed, no mass transfer layer was able to form. For building up a general framework of triboiogical behavior of the coated silver films, all test data were summarized on a map whose axes are contact pressure and sliding speed.

은 박막이 코팅된 표면에서 물질전이층의 형성 및 그 트라이볼로지적 역할에 관한 연구 (A Study on the Formation and the Tribological Role of Mass Transfers Layers at Rubbing Silver-coated Surface)

  • 양승호;공호성;윤의성;김대은
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 2002년도 제35회 춘계학술대회
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    • pp.45-52
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    • 2002
  • The tribological role of mass transfer layer was studied with silver coatings under various ranges of load and sliding speed. Silver coating was performed with a functionally gradient coating method. Tests were performed in dry sliding conditions, using a ball-on-disk contact configuration, at the load of 0.0196-17.64 N and the sliding speed of 20-1,000 mm/s in ambient air. Optical microscope and EPMA analyses showed that contact surfaces were covered with the mass transfer layers of agglomerated wear particles depending upon the contact conditions, and they greatly influenced the tribological characteristics of the surfaces. However, the formation of mass transfer layer was suppressed as the sliding speed increased, and above a critical sliding speed, no mass transfer layer was able to form. For building up a general framework of tribological behavior of the coated silver films, all test data were summarized on a map whose axes are contact pressure and sliding speed.

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프로세스 대형 모터-발전기의 저어널 베어링 설계 개선 - Part II : 로터다이나믹스 해석 (Journal Bearing Design Retrofit for Process Large Motor-Generator - Part II : Rotordynamics Analysis)

  • 이안성
    • Tribology and Lubricants
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    • 제28권6호
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    • pp.265-271
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    • 2012
  • In the preceding Part I study, for improving the unbalance response vibration of a large PRT motor-generator rotor fundamentally by design, a series of design analyses were carried out for bearing improvement by retrofitting from original plain partial journal bearings, applied for operation at a rated speed of 1,800 rpm, to final tilting pad journal bearings. To satisfy evenly key basic lubrication performances such as the minimum lift-off speed and maximum oil-film temperature, a design solution of 5-pad tilting pad journal bearings and maximizing the direct stiffness by about two times has been achieved. In this Part II study, a detailed rotordynamic analysis of the large PRT motor-generator rotor-bearing system will be performed, applying both the original plain partial journal bearings and the retrofitted tilting pad journal bearings, to confirm the effect of rotordynamic vibration improvement after retrofitting. The results show that the rotor unbalance response vibrations with the tilting pad journal bearings are greatly reduced by as much as about one ninth of those with the plain partial journal bearings. In addition, for the tilting pad journal bearings there exist no critical speed up to the rated speed and just one instance of a concerned critical speed around the rated speed, whereas for the plain partial journal bearings there exist one instance of a critical speed up to the rated speed and two instances of concerned critical speeds around the rated speed.

산소공장 공기터보압축기(ATC)의 회전체동역학 설계특성 분석 및 진동저감 (Analysis of Rotordynamic Design Characteristics and Vibration Reduction of an Air Turbo Compressor for Oxygen Plant)

  • 김병옥;이안성
    • 한국유체기계학회 논문집
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    • 제13권3호
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    • pp.43-48
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    • 2010
  • In this study rotordynamic characteristics of an air turbo-compressor (ATC) used in oxygen plant are analyzed and its operating-speed balancing is performed to solve the vibration trouble caused by rotor unbalance. Three dimensional model of the ATC rotor is completed and then analytical FE (finite element) model, which is verified by experimental modal testing, is developed. A rotordynamic analysis includes the critical map, Campbell diagram, and unbalance response, especially considering the pedestal housings supporting tilting pad bearings. A test run of operating-speed, using tilting-pad bearing of actual use, showed that the vibration level increased very sharply as approaching the rated speed. The operating-speed balancing specified by API 684 was carried out by using influence coefficient method. The results showed that the vibrations at the bearing pedestal housings represented good levels of 0.1 mm/s. From the test run and operating-speed balancing, the analytical results, that is, critical speeds are in good agreement with the test results and unbalance responses introducing the correction masses are similar to the as-is test responses in its aspect.

압전형 부하 센서링이 장착된 5축 절삭가공기의 고속 주축시스템 설계 (Design of High Speed Spindle for 5-Axis Machining Equipment Equipped with Piezo-Electric Load Sensoring)

  • 최현진;박철우;장은실;김충현;최성대
    • 한국기계가공학회지
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    • 제10권5호
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    • pp.20-25
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    • 2011
  • In this paper, we reviewed the spindle system's motor and bearing and its mode safety for optimal design of a high speed spindle system that exceeds DmN value of 1,500,000. We could verify that it has a separation margin during critical speed by performing critical speed analysis. Also, we have selected an optimal sensoring installation location and actually manufactured & installed the sensor by identifying the stress concentration position in the axial load through finite element analysis to install the built-in piezo electric type load sensor to the spindle housing that can measure and monitor the machining load during high speed rotation of the spindle. Reproducibility is also verified by calibrating the error through the sensor's sensitivity adjustment after comparing the output between the plate dynamoneters and the load sensor to confirm the reproducibility of the load sensor.

물 분사 펌프 동특성의 해석적 평가 (Analytical evaluation of water injection pump dynamic characteristic)

  • 이종명;이정훈;하정민;안병현;구동식;최병근
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2013년도 춘계학술대회 논문집
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    • pp.60-64
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    • 2013
  • Water injection pump produced the 1st oil well through the high pressure after the Deep water oil well drilling. After finish the work it is hard to produce only using itself pressure due to low pressure. Therefore it can be increased recovery factor through the injection seawater of high pressure. Is the key equipment used in the marine plant and it is developing at many industries. In this paper, Analyze changes in the natural frequency due to the stiffness of the bearing. Analyze the critical speed of the natural frequency due to the change of operation speed. And evaluate the Stability. And then analyze the displacement and clearance through the unbalance response this way has contributed to the reliability of the developing product. Through a mathematical analysis.

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동 다이캐스팅 고속 유도전동기의 불평형 응답 해석 (Unbalance Response Analysis of Copper Die Casting High Speed Induction Motor)

  • 홍도관;정승욱;우병철;구대현;안찬우
    • 한국소음진동공학회논문집
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    • 제22권7호
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    • pp.642-649
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    • 2012
  • This paper deals with a copper die casting induction motor which has several advantages of motor performance. The developed motor is used as spindle motor in machining center. The dynamic characteristic analysis of rotor is dealt with for precision machining. The critical speed of rotor considering rotation and gyroscopic effect should be above operating speed, 18,000 rpm, and have a 201 % sufficient separation margin. Also, the 3-D unbalance vibration response analysis is performed and enabled the prediction of the expected vibration amplitude by unbalance in high speed. The unbalance vibration responses of each position on the rotor are satisfied with allowable vibration displacement of API 611 standard according to balancing G grade(G 0.4, G 2.5, G 6.3). Copper die casting high speed induction motor is successfully developed and verified by experiment.

The role of mass transfer layer on the tribological characteristics of silver-coated surfaces

  • Yang, Seung-Ho;Kong, Ho-Sung;Yoon, Eui-Sung;Kim, Dae-Eun
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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    • pp.153-154
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    • 2002
  • Wear map of silver coatings on AISI 52100 has been constructed to delineate the wear transition behavior with the change in operating conditions in various environments. Three main regimes were clearly identified: (i) elastic/plastic deformation of silver coating without failure. (ii) mild wear regime after initial failure of silver coating and (iii) severe wear regime. In the mild wear regime, the contact surfaces were covered with transfer layers of agglomerated wear particles. The transfer layer acted as a protective layer and resulted in low friction even after the initial failure of the coated films, whose characteristics were strongly dependent on both the operating and environmental conditions. Also, the existence of the critical sliding speed, above which no transfer layer was able to form, was discussed in the work.

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FPGA 에 대한 지연시간 최적화 알고리듬 (Delay optimization algorithm on FPGAs)

  • 허창우;김남우
    • 한국정보통신학회논문지
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    • 제10권7호
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    • pp.1259-1265
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    • 2006
  • 본 논문에서는 고속 FPGA 설계를 위한 논리 수준의 조합회로 합성 알고리듬을 제안한다. 제안된 알고리듬은 회로의 지연시간을 줄이기 위해 critical path를 분할한다. 그리고 분할된 회로를 동시에 수행하는 구조를 갖는 회로를 생성한다. 본 커널 선택 알고리듬은 SUN UNIX 환경에서 C 언어로 구현되었다. 제안된 커널 선택 알고리듬은 기존의 FlowMap 지연시간 최적화 알고리듬과 결과를 비교하였다. 제안된 지연시간 최적화 알고리듬이 기존 알고리듬 에 비해 지연시간이 평균 33.3 % 감소된 회로를 생성함을 보였다.