• Tribology and Lubricants
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• 제23권2호
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• pp.43-48
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• 2007

Leakage reduction through annular type labyrinth seals of steam turbine is necessary for enhancing their efficiency. In this study, modified geometry of the original combination-type-staggered-labyrinth seal has been suggested and numerical analysis for leakage prediction has been carried out for the modified-combination-type-staggered-labyrinth seal both based on bulk-flow model and using the CFD code FLUENT. The theoretical analysis based on bulk-flow model yields leakage reduction of the modified combination type staggered labyrinth seal by about 11%. Comparing with the result of Bulk-flow model analysis, the leakage result of CFD analysis shows reasonable agreement within 9.8% error.

• Tribology and Lubricants
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• 제18권1호
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• pp.24-33
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• 2002

The basic equations are derived for the analysis of a staggered labyrinth gas seal which are generally used in high performance compressors and steam turbines. The Bulk-flow is assumed for a single cavity control volume and the flow is assumed to be completely turbulent in circumferential direction. Moody's wall-friction-factor formula is used for the calculation of wall shear stresses in the single cavity control volume. For the reaction force developed by the seal, linearized zeroth-order and first-order perturbation equations are developed for small motion about a centered position. Integration of the resultant first-order pressure distribution along and around the seal defines the rotordynamic coefficients of the staggered labyrinth gas seal. Theoretical results of leakage and rotordynamic characteristics for the staggered labyrinth gas seal are compared with those of the plain seal and see-through labyrinth seal.

• 대중서사연구
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• 제25권4호
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• pp.135-158
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• 2019

본고의 목적은 기예르모 델 토로의 <판의 미로>(2006)를 환상영화로 평가하게 해주는 특성과 그것에 밀접하게 결부되어 나타나는 미궁의 모티프의 의미와 기능을 고찰하는 데 있다. 츠베탕 토도로프는 '환상적인 것'을 현실에 침입한 초자연적인 사건에 직면하여 자연적 해석과 초자연적 해석 사이에서 겪는 망설임이라고 정의하였는데, <판의 미로>는 그 망설임이 사라져 환상적인 것이 '기이'장르나 '경이'장르로 들어가도록 하지 않고 그 상태가 그대로 유지되도록 하기 때문에 이 영화에서는 환상성이 계속해서 잘 드러난다. 이때 미궁은 환상계로 들어가는 통로이자 그것을 대표하는 공간으로서 예술을 상징한다. 로즈메리 잭슨은 환상이 "문화적 속박으로부터 비롯된 결핍을 보상하려고 하는 욕망의 문학"이어서 무의식적 제재들을 반복적으로 다룬다고 보았는데, 델 토로의 영화는 환상 세계에서 가족 로맨스가 이루어지도록 함으로써 욕망의 표현으로서의 환상의 특성을 잘 보여준다. 이때 미궁은 욕망의 장소로서 마음을 상징한다. 캐스린 흄은 환상이 미메시스와 같이 현실에 대한 반응이자 '일치된 현실로부터의 이탈'이라고 정의하였는데, 이 영화는 '비전'장르로서 '대조'의 방법을 통해 환상계가 현실계를 비추도록 함으로써 그 정의를 충족시키고 그것이 가진 환상성을 돋보이게 한다. 이때 미궁은 현실계의 거울로서 세계를 상징한다. 이처럼 <판의 미로>는 환상적인 것이 매우 효과적으로 기능한다는 점에서 환상영화를 대표할 만하며, 이 영화에 나타난 미궁은 예술, 세계, 마음의 세 가지를 모두 상징하여 의미가 충만한 모티프라고 평가할 수 있다. 본고의 의의는 위와 같은 고찰을 통해 한 모티프가 특정 장르에서 작용하는 방식을 조명한 데 있다.

• Journal of Mechanical Science and Technology
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• 제18권5호
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• pp.830-837
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• 2004

In this paper, the flow properties of staggered labyrinth seals are investigated. Leakage flowrates and pressure distributions are calculated for this seal. Then the dynamic stiffness and damping coefficients are calculated. The results are compared to the results of the some other papers.

• Tribology and Lubricants
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• 제25권5호
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• pp.298-304
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• 2009

An angled labyrinth seal is used for the diaphragm-packing-ring seal design of steam turbine due to its leakage reduction characteristic. CFD analysis using FLUENT has been performed to predict leakage and determine an optimum slanted angle which yields the best leakage reduction. Results show that the optimum value of slanted angle is $-30^{\circ}$ independent of number of labyrinth teeth, inlet pressure, and tooth height to pitch ratio. 3D CFD analysis has been performed for predicting leakage of the angled labyrinth seal. Comparing with the result of 2D CFD analysis, 3D CFD analysis shows 1.4% smaller.

• Tribology and Lubricants
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• 제12권4호
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• pp.35-42
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• 1996

The labyrinth seal is one of the widely used non-contact type mechanical seal. Current work was emphasized on the investigation of the air jet effect on the labyrinth seal. To improve the sealing capability of conventional labyrinth seal, air jet was injected against through the leakage flow. In this study, both of the numerical analysis by CFD (Computational Fluid Dynamics) and the experimental measurement were carried out. Both of the turbulence aad the compressible flow model were introduced in CFD analysis. The sealing effect of the leakage clearance and the air jet magnitude were studied in the experiment. The reason of the enhanced sealing was explained as a reduction of effective clearance by jetting air. As a result, the air jet could reduce the effective clearance with a wide range of leakage clearance.

• 소음진동
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• 제8권5호
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• pp.849-855
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• 1998

An analysis of lateral hydrodynamic forces of compressor labyrinth seals is presented. Basic equations are derived using a two-control-volume model for compressible flow. Blasius' wall friction-factor formula and jet flow theory are used for the calculaton of wall shear stresses and recirculation velocity in the cavity. Linearized zeroth-order and first-order perturbation equations are developed for a small motion about the centered position by expansion in the eccentricity ratio. Integraton of the resultant first-order pressure distribution over the seal defines the rotordynamic coefficients. As an application a rotordynamic analysis of the balance drum labyrinth seal found in an ethylene regrigeration copmressor is carried out. The rotordynamic characteristic results of the labyrinth seal are presented and compared with other types of seals, honeycomb seal and smooth seal.

• 한국지열·수열에너지학회논문집
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• 제10권1호
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• pp.1-6
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• 2014

In order to evaluate the performance of ground heat source in thermal labyrinth on pre-heating in winter season and pre-cooling in summer season, the followings are made as a conclusion through case study of H project by using the weather data from Korea meteorological administration and CFD model. By making outdoor air inlet via ground heat source in thermal labyrinth for conduction, convection and etc., the temperature rise is $13.4^{\circ}C$as the effect of pre-heating in winter season. On the other hand, as the effect of pre-cooling in summer season, the temperature decrease is $7.2^{\circ}C$. The energy saving rate by the application of ground heat source in thermal labyrinth is 9.1%.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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• pp.138-144
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• 1997

The analysis of lateral hydrodynamic forces from the compressor labyrinth seals is presented. The basic equations are derived using a two-control-volume model for compressible flow. Blasius' wall friction-factor formula and jet flow theory are used for the calculation of the wall shear stresses and the recirculation velocity in the cavity. Linearized zeroth-order and first-order perturbation equations are developed for small motion about a centered position by an expansion in the eccentricity ratio. Integration of the resultant first-order pressure distribution along and around the seal defines the rotordynamic coefficients of the labyrinth seal. The rotordynamic analysis for the balance drum labyrinth seal of an ethylene refrigeration compressor is carried out. The results of rotordynamic characteristic of the labyrinth seal and comparisons with other types of seal, honeycomb seal and smooth seal, are presented.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1149-1149
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• 2006

The leakage characteristic is an important factor in power plant. However, most of power plant have efficiency problem which is occurred leaking between high pressure steam turbine axle and stator. The labyrinth seal which is used between the main turbine axle and stator in the power plant. Because it is able to be non-contact seal and it is minimize clearance to decrease the leakage. But its actual system is too huge to experiment. Therefore, most steam turbine seal performance tests were conducted by air similarity test. This paper described a test facility and program for air similarity test of high pressure steam turbine seal. A test facility has been designed and built to evaluate leakage verification of labyrinth seal. The test facility consist of air compressor, anti-swirl labyrinth seal for 1/3 air similarity model, pressure transducer, air flow measure system, instrumentation and auxiliary system. For evaluation of steam turbine seal performance, the air similarity test of labyrinth seal leakage verification was conducted and we compared experiment data and analysis result.