• Title/Summary/Keyword: 누설유량

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Correlation between the Potential Barrier and Variation of Temperature on SiOC thin film (탄소 주입 실리콘 산화 절연박막에서 전위장벽과 온도 변화에 대한 상관성)

  • Oh, Teresa
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.12 no.12
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    • pp.2247-2252
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    • 2008
  • The SiOC films as the carbon doped silicon oxide film were prepared with the variation of flow rater ratios by plasma enhanced chemical vapor deposition. The samples were analyzed by the fourier transform infrared spectroscopy, I-V measurement and scanning electron microscopy. The samples were shown the chemical shift according to the flow rate ratios, and the grain did not formed at the sample with hybrid properties. The leakage currents decreased according to the increasing of the substrate temperature at the sample with hybrid properties, but the potential barrier increased.

Effects of Lobe Shapes on the Performance of Roots-Type Vacuum Pump (로브 형상 변화가 루츠형 진공 펌프 성능에 미치는 영향)

  • Kim, H.-J.;Kim, Youn J.;Hwang, Y.-K.
    • The KSFM Journal of Fluid Machinery
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    • v.3 no.2 s.7
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    • pp.50-56
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    • 2000
  • The effects of lobe shapes on the leak flow conductance of Roots-type vacuum pump are studied numerically and experimentally. The modelled lobe shape of Roots-type vacuum pump is two-lobe spur gear. The numerical analyses are performed on leak flows in Roots-type vacuum pump. It is numerically calculated using a 4th-order Runge-Kutta method and is compared with experimental results. Results show that for the case of involute lobe shape the total amount of the leak flow conductance is greater than that of cycloid and Cassini oval lobe shapes.

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An Experiments and Characterisics Analysis of the Sealless Cylinder (씰리스 실린더의 특성 해석 및 실험)

  • Kim, Young-Cheol;Kim, Dong-Soo;Bae, Sang-Kyu;Kim, Sung-Jong
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.980-985
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    • 2004
  • This paper shows a performance analysis for conical type sealless cylinders and rod bearings. The pistons without seal have partly cylindrical and conical shapes. 2 dimensional Reynolds equation and FD(finite differential) numerical techniques are utilized for the performance analysis. The relationship among self-centering forces and leakage flows are investigated. Also, optimal design values for a sealless cylinder are presented. A prototype of sealless cylinder which had rod bearing with four pockets, five pockets, and six pockets was manufactured respectively. Leakage flow test is conducted to evaluate performance of piston and rod bearing in sealless cylinder.

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Theoretical Analysis of the Slipper Hydrostatic Bearing Shape in the Swash Plate Type Axial Piston Pump (사판식 유압 피스톤 펌프의 슬리퍼 정압베어링면 형상에 관한 이론해석)

  • Cho, I.S.
    • Journal of Drive and Control
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    • v.10 no.1
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    • pp.14-20
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    • 2013
  • In the high rotational speed and pressure state, the leakage flow rate of the axial piston pump is one of the serious problems and make great reasons to decrease the volume efficiency. In this study, tribology characteristics is clarified for the hydrostatic slipper bearing in the swash plate type axial piston pump, by means of theoretical analysis for the different shape of the hydrostatic slipper bearing. It was analyzed by Mathcad software and used equal conditions at $0^{\circ}$ swash plate angle in each model. The results show that performance characteristics of the swash plate type axial piston pump are significantly influenced by the shape of the hydrostatic slipper bearing.

A Study on the Hydrostatic Test of Slipper Pad for Hydraulic Piston Motor (유압 피스톤모터용 Slipper Pad의 정압시험에 관한 연구)

  • 함영복;김광영;김형의
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.04a
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    • pp.645-649
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    • 1997
  • In case of swash plate type axial piston hydraulic motor, hydrostatic bearing used to achieve the lubrication effect on the mechanical sliding contact areas between the following parirs ; sliooer-pad and swash plate,piston and cylinder bore,valve plate and cylinder block, etc. This study discussed the basic charateristic for the hydrostatic slipper-pad bearings with the capillary or orifice restrictor under static load condition. And, we also development of hydrostatic bearing tester for hydrostatic balancing test of pistion & slipper-pad assembly, and some experimental data on supply pressure step responce are reported.

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Charncteristics Analysis of the Pneumatic Servo Cylinder (공기압 서보 설린더 특성 해석)

  • Kim, Dong-Soo;Kim, Kang-Dae;Kim, Myoung-Sub;Hur, Shin
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.1244-1249
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    • 2008
  • This paper shows a perfonnance analysis for pneumatic servo cylinder. The pistons without seal have partly cylindrical and conical shapes. 2 dimensional Reynolds equation and FD(finite differential) numerical techniques are utilized for the perfonnance analysis. The relationship among self-centering forces and leakage flows are investigated. Also, optimal design values for a servo cylinder are presented. A prototype of servo cylinder which had rod bearing with four pockets, five pockets, and six pockets was manufactured respectively.

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Development of Standard Procedures for Local Leakage Rate Testing of Containment Vessel (격납건물 국부누설률시험 표준절차 개발)

  • Moon, Yong-Sig;Kim, Chang-Soo
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.8 no.2
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    • pp.42-47
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    • 2012
  • The containment local leakage rate testing in nuclear power plants is performed in accordance with ANSI/ANS 56.8-1994 in Korea. Two methods, the make-up flow rate and the pressure decay, are used for local leakage rate testing. Though ANSI/ANS 56.8-1994 does not define clearly the minimum test duration for the make-up flow rate method, it requires obtaining the data after reaching the stable condition. Thus the prerequisite stable condition for data acquisition and the testing time is differently applied to each NPPs. Therefore, this study presents a standardized test procedure for data stabilization and testing time through experiments to improve the test reliability.

Numerical Study of The Nozzle-Rotor Axial Gap Effect on the Supersonic Turbine Performance (충동형 초음속 터빈의 노즐-로터 축간극에 따른 성능변화 연구)

  • Jeong, Soo-In;Kim, Kui-Soon;Jeong, Eun-Hwan
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.11a
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    • pp.160-163
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    • 2010
  • We performed three-dimensional CFD analysis to investigate the effect of the nozzle-rotor axial gap of a partial admission supersonic turbine on the stage performance and the flow field. The computations are conducted for five axial gaps using flow analysis program, $FLUENT^{TM}$. The results show that the axial gap between nozzle and rotor give the effect on the mass flow rates of tip leakage and the flow angle at the rotor outlet.

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An Analysis and Test for Leakage Flow of Sealless Cylinder (고성능 씰리스 실린더의 해석 및 누설유량 시험)

  • Kim, Sung-Jong;Kim, Dong-Soo;Lee, Seung-Hyun
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.961-966
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    • 2004
  • The cylinder without seal has a piston with air bearing which is partly cylindrical and conical shape. The description of system geometry is deviation by the flow rate equation. Then pressure distribution and bearing force equations are derived. Several non-dimensional parameters are suggested. The relationship among bearing force, leakage flow and geometry of the bearing is investigated by simulation. And determination method for optimal design of sealless cylinder is given. A prototype of sealless cylinder which had rod bearing with four pockets, five pockets, and six pockets was built respectively. As a result of leakage flow test, it is evaluation to air bearing in sealless cylinder.

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A Study on Lubrication Characteristic of the Hydrostatic Bearing In Swash Plate Type Piston Motor (사판식 피스톤 모터의 정압베어링 윤활특성에 관한 연구)

  • Lee, Yong-Bum;Kim, Kwang-Min
    • Journal of Power System Engineering
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    • v.15 no.5
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    • pp.5-9
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    • 2011
  • The hydraulic piston using a hydrostatic bearing has been used widely due to its satisfying performance at very high pressurized circumstance and relative higher power density in comparison to conventional one. For high pressurization, enhanced efficiency and long durability of the hydraulic piston, the design of hydrostatic bearing is at issue, which is installed between piston shoe and swash plate. The performance of the hydrostatic bearing is influenced significantly by the assembly of the piston shoe consisting of circular land and recess. In this study, to estimate the performance of the hydrostatic bearing, the characteristics for lubrication of the assembly of the piston shoe were investigated by measuring a leakage rate of hydraulic fluid under an experimental condition, where a rotating velocity of the piston, hydraulic pressure and temperature of the hydraulic fluid were changed systematically. In addition, a film thickness of the hydraulic fluid on the piston shoe was measured and compared to theoretical one.