• Title/Summary/Keyword: LOP type

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Experimental Study on the Characteristics of the Film Pressure and Temperature in a 5-Pad Tilting Pad Journal Bearing of LOP Type (LOP형 5패드 틸팅패드 저어널베어링의 압력 및 온도 특성에 관한 실험적 연구)

  • 하현천;양승헌;변형현
    • Tribology and Lubricants
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    • v.14 no.1
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    • pp.7-13
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    • 1998
  • The static characteristics of a five-pad tilting pad journal bearing of load on pad (LOP) type have been investigated experimentally under the different values of bearing load and shaft speed. The diameter and length of the bearing are 300.91 mrn and 149.8 mm, reslx;ctively. Circumferential distribution of the film pressure, film thickness, journal surface temperature and beating surface temperature are measured. A noticeable inlet pressure rise is observed at the entrance of each pad, especially the bottom pad. The inlet pressure is increased by the increase of shaft speed as well as bearing load. In the five-pad tilting pad joumal bearing of LOP type, almost all of beating load is being carried only by the bottom pad. The maximum bearing surface temperature is observed at near the minimum film thickness. It is observed that the metal temperature of the mid-plane is higher than that of the edge at the inlet region, while the metal temperature of the edge is higher than that of the mid-plane at the outlet region.

A Study on the Internal Temperature Reduction of PKG-A Water-jet-room by Substituting Heat Insulation Materials (단열재 개선을 통한 PKG-A Water Jet Room 온도저감 연구)

  • Jung, Young In;Choi, Sang Min
    • Journal of Korean Society for Quality Management
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    • v.47 no.3
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    • pp.425-435
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    • 2019
  • Purpose: The purpose of this study was to resolve the Naval ship's Local Operation Panel(LOP) malfunction problems which caused by overheating in summer season and dispatching to equatorial regions. Methods: Instead of using dual type heat insulation materials(consist with ceramic wool and glass wool), aerogel heat insulation materials were used for decreasing heat emissions from gas-turbine heat waste steam pipes passing water-jet- room. Experiment and Computational analysis of heat flow were conducted to analyze the internal room temperature changes. Results: The results of this study are as follows; The aerogel heat insulation materials suppress heat emission more efficiently than dual type insulation materials. The cold surface temperature of insulation was far more decreased and internal room, LOP surface temperature also showed significant results too. Conclusion: The substituted heat insulation materials appeared remarkable performance in decreasing room temperature that it could be used for suppressing the LOP overheatings and malfunctions.

Effects of Design Conditions in Five Pad Tilting Pad Bearing on the Lateral Vibration Characteristics of Small Gas Turbine (5패드 틸팅 패드 베어링의 설계 조건 변화가 소형 가스터빈의 횡진동 특성에 미치는 영향)

  • Ha, Jin-Woong;Myung, Ji-Ho;Suk, Jhin-Ik;Lee, An-Sung;Kim, Young-Cheol
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.8
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    • pp.752-760
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    • 2011
  • In tilting pad bearing design process, the selection of the proper configuration type of either a load-between-pad(LBP) or load-on-pad(LOP) as well as preload and pivot offset conditions is to be carefully considered. Also the bearing needs to be designed in order to be suited for the rotor-bearing system and operating condition. In this paper, it is observed that the dynamic characteristics in a five pad tilting pad bearing for the LBP and the LOP configurations are influenced by the variation of preload and pivot offset. In this context, rotor dynamic analysis of the 5 MW industrial gas turbine supported by the tilting pad bearing at the front and roller bearing at the rear is carried out based on the dynamic coefficients of the tilting pad bearing investigated. The result shows that two rigid body critical modes experience various changes according to the influence of the tilting pad bearing uniquely applied to one side of this machine. Mainly, the second critical speed, the rigid body mode of conical shape with high whirling in the tilting pad bearing, is significantly changed by preload and pivot offset regardless of the LBP and LOP configurations. And, the first critical mode, the rigid body mode of conical shape with high whirling in the roller bearing, is sensitively affected by preload applied to the LOP configuration and by its asymmetric dynamic properties.

Effects of Design Conditions in Five Pad Tilting Pad Bearing on the Lateral Vibration Characteristics of Small Gas Turbine (5패드 틸팅 패드 베어링의 설계 조건 변화가 소형 가스터빈의 횡진동 특성에 미치는 영향)

  • Ha, Jin-Woong;Myung, Ji-Ho;Suk, Jhin-Ik;Lee, An-Sung;Kim, Young-Cheol
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2011.04a
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    • pp.425-432
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    • 2011
  • In tilting pad bearing design process, the selection of the proper configuration type of either a Load-Between-Pad (LBP) or Load-On-Pad (LOP) as well as preload and pivot offset conditions is to be carefully considered. Also the bearing needs to be designed in order to be suited for the rotor-bearing system and operating condition. In this paper, it is observed that the dynamic characteristics in a 5 pad tilting pad bearing for the LBP and the LOP configurations are influenced by the variation of preload and pivot offset. In this context, rotor dynamic analysis of the 5MW industrial gas turbine supported by the tilting pad bearing at the front and roller bearing at the rear is carried out based on the dynamic coefficients of the tilting pad bearing investigated. The result shows that two rigid body critical modes experience various changes according to the influence of the tilting pad bearing uniquely applied to one side of this machine. Mainly, the second critical speed, the rigid body mode of conical shape with high whirling in the tilting pad bearing, is significantly changed by preload and pivot offset regardless of the LBP and LOP configurations. And, the first critical mode, the rigid body mode of conical shape with high whirling in the roller bearing, is sensitively affected by preload applied to the LOP configuration and by the its asymmetric dynamic properties.

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Comparison Between Conservation System of a Coastal Type of National Park of Korea and Japan - Focused on Taean-Haean National Park - (해안형 국립공원의 보전체계에 대한 한.일 비교 - 태안해안 국립공원을 중심으로 -)

  • Jo, Tae-Dong;Okano, Takahiro
    • Journal of Environmental Science International
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    • v.12 no.2
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    • pp.151-155
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    • 2003
  • The resources conservation system is comprehended, making Taean-haean National Park a research material by applying the fact of landowning, designating an LOP and Korea and Japan's Natural Park Act. Following conclusions were obtained in this study; Most of land areas of the National Park are privately owned; Only a few have been designated as Natural Reservation, a core reserved area on LOP, and a sandy beach, a sand dune, a sand spit, a tidal flat, a wetland, etc are distributed in the natural environment area so they were exposed to development; As seen in most of coastal type of National Parks, 13 commercial beaches are established. The annual rush to the beaches appears in July and August; Sand dune areas that have to be managed in terms of conservation, are turned into beaches. Moreover, the collective facilities areas are randomly developed. So they fail to function originally; The current Natural Park Act has no systematic devices for conservation of the natural resources on the seashore or offshore.

Study on the Characteristics of the Upper Pad Fluttering in a 6-Pad, LOP Type, Tilting Pad Journal Bearing (LOP형 6-패드 틸팅패드 저널베어링의 상부패드 Fluttering 특성 연구)

  • 양승헌;박희주;박철현;김재실
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.13 no.6
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    • pp.467-473
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    • 2003
  • This paper describes the fluttering characteristics of the upper pad in a tilting pad journal bearing(6-pad, LOP type) using a steam turbine. In order to investigate the phenomena of the upper pad fluttering experimentally, the absolute vibration of the upper pads, the relative vibration between bearing and shaft and the circumferential distribution of the film thickness are measured under the different values of supply oil flow rate, shaft speed and bearing load. It can be known that the fluttering mechanism of the upper pads has a tendency of the self-excited vibration from the study of fluttering frequencies and amplitudes with the change of shaft speed. Furthermore, it is observed that the incipient upper pad fluttering velocity is increased by the increase of oil supply flow rate and the fluttering amplitude of the upper pads is increased by the decrease of the ell flow rate and by the increase of the bearing load.

A Study on Estimation of Infinite Fatigue Life in Cruciform Fillet Welded Joint (십자형 필릿 용접부에서의 무한 피로수명 평가에 관한 연구)

  • Lee, Yong-Bok
    • Journal of the Korean Institute of Gas
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    • v.17 no.1
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    • pp.19-25
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    • 2013
  • The joining methods of steel structures of gas facilities, bridges, ships etc. by welding are composed mostly of T-type or cruciform fillet welding and full penetration or partial penetration according to the uses and the shape of the structures. In this study, it was examined the characteristics of fatigue crack according to penetration depth in relation to material thickness in the cruciform fillet welded joints. From the results, it was investigated the safe design stresses within the range of infinite life. When the LOP length is long the range of infinite life is small with root failure and when the LOP length is short the range of infinite life is large with teo failure. For the specimen of material thickness, 20mm welded by 3 pass compared with 10mm, 15mm welded by 2 pass, the fatigue strength and the range of infinite life was more improved by increasing of notch toughness from formation of micro-ferrite acicular structure.

Experimental Study on the Stiffness and Damping Coefficients of a Tilting Pad Journal Bearing (틸팅패드 저널베어링의 유막 강성 및 감쇠계수에 대한 실험적 연구)

  • Ha, Hyun-Cheon;Yang, Seong-Heon
    • The KSFM Journal of Fluid Machinery
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    • v.2 no.2 s.3
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    • pp.32-38
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    • 1999
  • An experimental study is performed to investigate the frequency effects of the excitation force on the linear stiffness and damping coefficients of a LOP (load on pad) type five-pad tilting pad journal bearing with the diameter of 300.91 mm and the length of 149.80 mm. The main parameter of interest in the present work is excitation frequency to shake the test bearing. The excitation frequency is controlled independently, using orthogonally mounted hydraulic exciters. The relative movement between the bearing and shaft, and the acceleration of the bearing casing are measured as a function of excitation frequency using the different values of bearing load and shaft speed. Measurements show that the variation of excitation frequency has quite a little effect on both stiffness and damping coefficients. Both direct stiffness and damping coefficients in the direction of bearing load decrease by the increase of shaft speed, but increase with the bearing load.

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Experimental Study on the Stiffness and Damping Coefficients of a Tilting Pad Journal Bearing (틸팅패드 저어널 베어링의 유막 강성 및 감쇠 계수에 대한 실험적 연구)

  • Ha, Hynn Cheon;Yang, Seong Heon
    • 유체기계공업학회:학술대회논문집
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    • 1998.12a
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    • pp.173-179
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    • 1998
  • An experimental study is performed to investigate the frequency effects of the excitation force on the linear stiffness and damping coefficients of a LOP (load on pad) type five-pad tilting pad journal bearing with the diameter of 300.91 mm and the length of 149.80 mm. The main parameter of interest in the present work is excitation frequency to shake the test bearing. The excitation frequency is controlled independently, using orthogonally mounted hydraulic exciters. The relative movement between the bearing and shaft, and the acceleration of the bearing casing are measured as a function of excitation frequency using the different values of bearing load and shaft speed. Measurements show that the variation of excitation frequency has quite a little effect on both stiffness and damping coefficients. Both direct stiffness and damping coefficients in the direction of bearing load decrease by the increase of shaft speed, but increase with the bearing load.

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Effects of Exciting Frequency on the Stiffness and Damping Coefficients in a Tilting Pad Journal Bearing (가진 주파수가 틸팅패드 저어널베어링의 강성 및 감쇠계수에 미치는 영향)

  • 하현천;양승헌;김호종
    • Tribology and Lubricants
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    • v.14 no.1
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    • pp.14-22
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    • 1998
  • This paper describes the effects of exciting frequency on the stiffness and damping coefticients of a 5-pad tilting pad journal bearing, LOP (load on pad) type. The stiffness and damping coefficients are investigated experimentally under the different values of exciting frequency, bearing load and shaft speed. These coefficients are estimated by measuring the response of the relative displacement between the bearing and the shaft and acceleration of the bearing due to the known exciting loads acting on the bearing. In order to analysis the response of exciting load, displacement and acceleration, a FFT analyzer is used. It is shown that the variation of exciting frequency has a little effect on both the stiffness and damping coefficients. Both the stiffness and damping coefficients in the loading direction are decreased by the increase of shaft speed but increased by the increase of bearing load.