• Title/Summary/Keyword: ring face wear

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Performance Analysis of Mechanical Face Seal Used for Primary Heat Transport Pump in Heavy Water Reactor (중수로 냉각재 펌프용 미케니컬 페이스 실의 성능 해석)

  • Kim, Jeong-Hun;Kim, Dong-Wook;Kim, Kyung-Woong
    • Tribology and Lubricants
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    • v.27 no.5
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    • pp.240-248
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    • 2011
  • Mechanical face seal installed in primary heat transport pump used for heavy water reactor prevents leakage of working fluid using thin working fluid film between primary seal ring and mating ring. If the leakage of working fluid exceeds the allowable volume, serious accident can be happened by the trouble of primary heat transport pump. The thinner fluid film exists between primary seal ring and mating ring, the less working fluid leaks out. On the other hand, if the thickness of fluid film is not enough, the life of mechanical face seal will be reduced by friction and wear. Therefore appropriate design is necessary to maximize the performance and life of mechanical face seal. In this study, numerical analysis using finite volume method was conducted to investigate the performance of mechanical face seals which have same deep straight groove and 11 different net coning values. As results, equilibrium clearance between primary seal ring and mating ring, leakage volume of working fluid, friction torque on sealing surface and stiffness of working fluid film were obtained. With increasing net coning value, equilibrium clearance and leakage volume increase, and friction torque and stiffness of fluid film decrease.

Finite Element Analysis for the Contact Behavior in Double-Type Mechanical Face Seals Used for Small Hydro Power Turbine (소수력 터빈용 복수 기계평면시일의 접촉거동에 관한 유한요소해석)

  • Kim, Chung-Kyun;Kang, Hyun-Joon
    • Tribology and Lubricants
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    • v.21 no.5
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    • pp.201-208
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    • 2005
  • This paper presents the FEM analysis on the contact behavior characteristics of mechanical face seals in a small hydro-power turbine. Especially, the axial displacement and contact normal stress between a seal ring and a seal seat of a primary sealing unit have been analyzed as functions of rotating speed of a hydro-turbine, sealing gap, water and cooling fluid temperature. Those are strongly related to a leakage of water and wear between a seal ring and a seal seat. The FEM computed results present that the rotating speed of a hydro-turbine may be kept less than 800 rpm, and the sealing gap in a primary sealing unit is restricted $0.5\~5$. The coolant temperature in which is most influential parameter to the contact behaviors of a sealing unit may be kept less than $15^{\circ}C$ for a safe operation of a sealing unit without a leakage and wear.

A Study on the Friction and Wear Characteristics of Contact Sealing Units for a Small Hydro-power Turbine Under Various Rubbing Conditions (마찰접촉조건에 따른 소수력 수차용 밀봉장치의 마찰.마멸특성 연구)

  • Kim, Chung-Kyun
    • Tribology and Lubricants
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    • v.22 no.6
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    • pp.314-319
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    • 2006
  • In this paper, the friction and wear characteristics of contact type sealing unit far a water turbine have been presented. The sealing unit for a small hydropower generation is to stop a leakage of circulating water from an outside of an impeller to an inside of a rolling bearing. The friction heating between a seal ring and a seal seat may radically increase a surface temperature in which increase a power loss and wear on the rubbing surface. The surface wear strongly affect to the seal life of a mechanical face seal. In this study, the hardness of a stainless steel in which is a heat-treated is 892.8 in Victors hardness and the hardness of silicone carbide of SiC is 714.1 in Victors hardness. The surface hardness of a heat-treated stainless steel is 25% high compared with that of a ceramic material of SiC. The contact modes of rubbing surfaces are a dry friction, a water film friction and a mixed friction that is contaminated by a dust, silt, and moistures, etc. These two factors of a contact rubbing modes and a material property are very important parameters on the tribological performance such as a friction and wear between a seal ring and a seal seat in primary sealing unit. The experimental result shows that the surface hardness of a seal material is very important on the friction coefficient and a wear volume. Thus, the results recommend higher hardness of a seal material, which may reduce a friction loss and increase a wear life of primary seal components.

Groove Design of a Gas Seal Including Friction Heatings (마찰열을 고려한 가스시일의 그루브 설계)

  • 김청균;조승현;고영배;차백순
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2000.06a
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    • pp.201-210
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    • 2000
  • The noncontacting groove end face seal is one of various approaches to sealing gases with a single seal. Gas pumped into groove maintains operating gap and lubricates between primary ring and mating ring. So it removes heat and decreases face wear. In this paper, K-type and T-type grooved seals have been analyzed numerically using the finite element method. It explains the effects of groove shapes in gas seals along rotating speeds with a temperature gradient, face distortion, stress and so on. The calculated FEM results show the operating gap and rotating speed are strongly related to the leakages of a gas seal and that T-type groove seal shows a good thermal performance compared to K-type groove seal.

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Optimized Sealing Profile Design of Mechanical Face Seals for a Hydro-power Turbine (소수력 터빈용 기계평면시일의 최적형상설계에 관한 연구)

  • Kim, Chung-Kyun;Kim, Jung-Il;Sihn, Ihn-Cheol;Lim, Kwang-Hyeon
    • 한국신재생에너지학회:학술대회논문집
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    • 2006.06a
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    • pp.499-502
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    • 2006
  • This paper presents computed results of FEM analysis on the tribological contact behaviors of a primary sealing components of mechanical face seals for a small hydro-power turbine. The FEM computed results present that the contact area between seal rings and seal seats is very important for a good tribological performance such as low friction heating, low wear, high contact normal stress in a primary seal ing components. Based on the FEM computation, model III in which has a small sealing contact area shows low dilatation of primary sealing components, and high contact stress between a seal ring and a 1)seal seat.

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Study on the Mechanical Face Seal Performance for a 7-ton-Class Turbopump (7톤급 터보펌프 기계평면실의 성능 시험 연구)

  • Bae, Joonhwan;Kwak, Hyun D.;Choi, Changho
    • Tribology and Lubricants
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    • v.32 no.5
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    • pp.154-159
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    • 2016
  • This paper presents an experimental study of the leakage performance and endurance performance of a mechanical face seal in the 7-ton-class turbopump of the Korea Space Launch Vehicle 2 third-stage engine. We install a mechanical face seal between the fuel pump and turbine to prevent the mixing of the fuel and turbine gas. We design and manufacture a prototype mechanical face seal, which has two parts, namely, a bellows seal assembly and mating ring. We set up a test facility to measure the leakage and endurance of the mechanical face seal. For the similarity tests, we use water under real operating conditions such as high rotational speed, high temperature, and high pressure. Through investigation of the leakage and carbon wear rate, it is possible to evaluate the performance of the mechanical face seal. The results of the leakage and endurance performance test demonstrate the absence of any leakage from the prototype mechanical face seal after a trial run and clarify that the acceptable wear rate fully satisfies the turbopump requirements. Finally, we install a qualified mechanical face seal in a 7-ton-class turbopump and perform a validation test in the turbopump real-propellant test facility in the Korea Aerospace Research Institute. The test results confirm that the mechanical face seal works well under real operating conditions.

Experimental Investigation of Thermal Stress Cracks in Mechanical Face Seals (기계평면시일의 열응력 크랙에 관한 실험적 연구)

  • 김청균
    • Tribology and Lubricants
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    • v.12 no.3
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    • pp.79-84
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    • 1996
  • One of the greatest dangers in mechanical face seals is the formation of heat checking and thermal stress cracks on the sliding surfaces. These thermal distortions due to non-uniform heating lead to increase the leakage of the sealed fluids and wear, and with balance of the seal can cause the seal faces to part. In this study heat checking and thermal stress cracks are investigated experimentally. These thermal distortions are explained using the thermal models of the conatct geometries between the seal ring and the seal seat. To overcome these thermal problems, the thermohydrodynamic seal is presented. The newly developed mechanical seal may substantially reduce the friction torque, frictional heating which causes heat checking and thermal stress cracks, and wear.

Experimental Study on the Friction and Wear Characteristics of Contact Sealing Unit for a Water Turbine (수차용 봉수장치의 마찰.마모특성에 관한 실험적 연구)

  • Kim, Chung-Kyun;Sihn, Ihn-Cheol;Lim, Kwang-Hyeon
    • 한국신재생에너지학회:학술대회논문집
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    • 2006.11a
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    • pp.515-518
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    • 2006
  • This paper presents the friction and wear characteristics of contact type sealing unit for a water turbine of a small hydro-power generation, which Is to stop a leakage of a circulating water from a outside of an impeller to an inside of a rolling bearing. The surface wear strongly affect to the seal life of a mechanical face seal. In this study, the hardness of a stainless steel in which is a heat-treated is 892.8 in Vickers hardness and the hardness of silicone carbide of SiC is 714.1 in Vickers hardness. The surface hardness of a heat-treated stainless steel is 25% high compared with that of a ceramic material of SiC. The contact modes of rubbing surfaces aye a dry friction a water film friction and a mixed friction that is contaminated by a dust, silt and moistures, etc. These two factors of a contact rubbing modes and a material property are very important parameters on the tribological performance such as a friction and wear between a seal ring and a seal seat. The experimental result shows that the surface hardness of a seal material is very important on the friction coefficient and a wear volume. Thus, the results recommend higher hardness of a seal material, which may reduce a friction loss and increase a wear life of primary seal components

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"A Study on Hebrews Clothing in the Old Testament" - Especially on Hair Styles, Headgears, Footwear and Personal Ornaments - (구약성서(舊約聖書)에 나타난 히브리인의 복식(服飾) - 두식(頭飾), 신발 및 장신구(裝身具) 중심(中心)으로 -)

  • Park, Chan-Boo
    • Journal of the Korean Society of Costume
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    • v.10
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    • pp.63-80
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    • 1986
  • The Old Testament cotains mention of the history of creation and clothing in ancient Hebrew. This study dealt with Hebrew dress customs especially aimed at the manners of their hair styles, headgears, footwear and personal ornaments. References are Korean Revised Version, English King James Version and Revised Standard Version. There is little mention of hair styles and headgears in the Old Testament. Some sort of turban was worn by priests, and soldiers protected themselves with helmets, but most Israelitish men went bareheaded except on special occasions and often wear simple headbands. It was more common for women to use headwear of some type-turbans, scarves, and veils concealing the face. The veil was the distinctive female wearing apparel. All females, with the exception of maidservants and women in a low condition of life, wore a veil. It was the custom for women to wear a veil entirely covering their head in the public. Through most of the Old Testament periods long and thick hair was admired on men and women alike. The Hebrews were proud to have thick and abundant long hair, and they gave much attention to the care of their hair. The caring of hair was deeply related to their rituals. Nazirites never took a razor to their hair during his vow-days, but instead let it grow long, as an offering to God. Men would not cut their beards, but allow them to grow long. The Israelites' standard footwear was a pair of simple leather sandals. This was one of the items of clothing not highly prized. In a colloquial saying of the time, a pair of shoes signified something of small value, and to be barefoot except in times of mourning or on holy place, was a sign either of extreme poverty or humiliation, as in the case of war prisoners. Because precious stones were not mined in the Palestine-Syria region, Hebrews imported them from foreign country. They were consumer-to a large degree limited by their very modest standard of living-but not producers. Hebrews liked the precious stones and were motivated to acquire and wear jewels. Besides their use for adornment and as gifts, the precious or semiprecious stones were regarded by Jews of property. The Hebrews were not innovators in the field of decorative arts. The prohibition of the Law against making any "graven image" precluded the development of painting, sculpture, and other forms of representational art. Jewish men did not indulge in extravagances of dress, and there was little ornamentation among them. Men wore a signet ring on their right hand or sometimes suspended by a cord or chain around the neck. The necklaces, when worn by a male, also bore any symbol of his authority. Bracelets were extremely popular with both men and women, men usually preferring to wear them on their upper arms. The girdle was a very useful part of a man's clothing. It was used as a waist belt, or used to fasten a man's sword to his body, or served as a pouch in which to keep money and other things. Men often carried a cane or staff, which would be ornamented at the top. Among the women there was more apt to be ornamentation than among the men. Hebrew women liked to deck themselves with jewels, and ornamentation of the bride were specially luxurious and numerous. They wore rings on their fingers or On toes, ankle rings, earrings, nosering, necklace, bracelets. Their shapes were of cresent, waterdrops, scarab, insect, animal or plant. Sometimes those were used as amulets. They were made of ceramics, gold, silver, bronze, iron, and various precious stones which were mostly imported from Egypt and Sinai peninsular. Hebrews were given many religious regulations by Moses Law on their hair, headgears, sandals and ornamentation. Their clothing were deeply related with their customs especially with their religions and rituals. Hebrew religion was of monotheism and of revealed religion. Their religious leaders, the prophets who was inspired by God might need such many religious regulations to lead the idol oriented people to God through them.

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