• Title/Summary/Keyword: labyrinth

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Leakage Analysis and Design Modification of the Combination-Type-Staggered-Labyrinth Seal (누설량 저감을 위한 래버린스 실의 설계개선 및 해석)

  • Ha, Tae-Woong
    • Tribology and Lubricants
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    • v.23 no.2
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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.

Leakage and Rotordynamic Analysis for Staggered-Labyrinth Gas Seal (엇갈린 래버린스 실의 누설량 및 동특성 해석)

  • Ha, Tae-Woong
    • Tribology and Lubricants
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    • v.18 no.1
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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.

The Fantastic and Labyrinth Motif in Pan's Labyrinth (<판의 미로>에 나타난 환상성과 미궁의 모티프)

  • Noh, Shi-Hun
    • Journal of Popular Narrative
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    • v.25 no.4
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    • pp.135-158
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    • 2019
  • The purpose of this paper is to elucidate the characteristics that make Guillermo del Toro's film Pan's Labyrinth (2006) a fantasy film, and the meaning and function of the labyrinth motifs closely related to it. Tzvetan Todorov defined the 'fantastic' as the hesitation between natural and supernatural interpretations in the face of supernatural events that invade reality. In Pan's Labyrinth, the fantastic continues to be seen, because the film does not allow the hesitation to disappear; thus, the fantastic does not enter the 'uncanny' genre or 'marvelous' genre, and because it keeps its fantastic state. In this case, the labyrinth symbolizes art as a passage into the fantastic world and a space that represents it. Rosemary Jackson saw the fantasy as a "literature of desire to compensate for a lack resulting from cultural constraints" and thus repeatedly dealing with unconscious materials. Del Toro's film shows the character of the fantastic as an expression of desire by allowing 'family romance' to take place in the fantastic world. In this case, the labyrinth symbolizes the mind as a place of desire. Kathryn Hume defined fantasy as a reaction to reality, like mimesis, and 'departure from consensus reality.' The film, operating in a 'vision' genre, satisfies its definition by allowing the fantastic world to illuminate the reality world through 'contrastive' technique, and brings out the fantastic it has. In this case, the labyrinth symbolizes the world as a mirror of the world of reality. Thus, Pan's Labyrinth is representative of fantastic film in that the fantastic functions very effectively, and the labyrinth appearing in this film can be evaluated as a motif that is full of meaning by symbolizing all three elements of art, world and mind. The significance of this paper is to shed light on how a motif works in a particular genre through the above considerations.

Walking the Labyrinth in the Korean Church ('래버린스 걷기'에 대한 고찰과 그 활용 방안)

  • Sam Jun Ryu
    • Journal of Christian Education in Korea
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    • v.75
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    • pp.127-152
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    • 2023
  • Purpose of study: This study aims to explore 'labyrinth walking,' a lesser-known Christian spiritual practice within the Korean church. Additionally, it intends to propose ways for implementing labyrinth walking through literature reviews encompassing theory and practice. Research content and method: The article begins with its exploration by defining labyrinth walking from a historical perspective. It was a spiritual practice that existed in the Middle Ages, involving the traversal of a labyrinthine shape, typically a single path on the floor, often accompanied by prayer or contemplation. The contemporary spiritual practice of labyrinth walking was recovered and reinterpreted by Christian scholars and spiritual directors during the mid and late twentieth century. Additionally, within Christianity, labyrinth walking, rich with symbolism representing Jesus' suffering and salvation, baptism, pilgrimage, and purification, comprises five essential steps: preparing, walking with prayer or contemplation, remaining in the center, returning, and journaling and sharing. By merging pilgrimage, walking, prayer, and meditation, the practice of walking the labyrinth can enable people to have an opportunity for retreat, to encounter and be accompanied by God, to experience moments of serenity and healing, to reflect on themselves, to create life-transforming resolutions, and to build a sense of community. As a result, many Korean churches should acknowledge the value of and utilize labyrinth walking to nurture faith and spirituality. Conclusions and Suggestions: Accordingly, this paper suggests some practical ways to employ labyrinth walking as a form of prayer, part of a ritual or religious activity, an embodiment of pilgrimage, and a tranquil and nonverbal experience. Furthermore, the study recommends that Korean churches establish proper goals, consider essential principles for labyrinth design and installation, and follow specific guidelines while conducting labyrinth walks.

Rotordynamic Coefficients in Staggered Labyrinth Seals

  • Eser, Dursun;Dereli, Yilmaz
    • Journal of Mechanical Science and Technology
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    • v.18 no.5
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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.

Leakage Analysis of Angled-Labyrinth-Packing-Ring Seal for Steam Turbine Using CFD (CFD를 사용한 스팀터빈용 각이 진 패킹 링 실의 누설량 예측)

  • Ha, Tae-Woong;Kang, Jung-Hyun
    • Tribology and Lubricants
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    • v.25 no.5
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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.

The Air Jet Effect of Sealing Performance Improvement on Labyrinth Seal (공기분사가 라비린스 시일의 성능개선에 미치는 영향)

  • 나병철;전경진;한동철
    • Tribology and Lubricants
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    • v.12 no.4
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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.

Rotordynamic Analysis of Compressor Labyrinth Seals (압축기용 라비린스 실의 동특성 해석)

  • 하태웅;이안성
    • Journal of KSNVE
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    • v.8 no.5
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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.

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Case Study on Application of Ground Heat Source in Thermal Labyrinth by CFD Model (CFD 모델을 이용한 열미로의 지중열원 활용에 관한 사례 연구)

  • Min, Joon-Ki;Nam, Sun-Young
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.10 no.1
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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%.

Rotordynamic Analysis for Labyrinth Seals Used in Compressors (압축기용 라비린스 실의 동특성 해석)

  • 하태웅;이안성
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1997.10a
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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.

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