• 제목/요약/키워드: 유리섬유 냉각장치

검색결과 3건 처리시간 0.015초

광섬유 고속인출공정용 유리섬유 냉각장치 내 공기유입에 의한 내부헬륨농도 저하현상 연구 (HELIUM CONCENTRATION DECREASE DUE TO AIR ENTRAINMENT INTO GLASS FIBER COOLING UNIT IN A HIGH SPEED OPTICAL FIBER DRAWING PROCESS)

  • 김경진;김동주;곽호상;박상희;송시호
    • 한국전산유체공학회지
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    • 제15권4호
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    • pp.92-98
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    • 2010
  • In a modern high speed drawing process of optical fibers, it is necessary to use helium as a cooling gas in a glass fiber cooling unit in order to sufficiently cool down the fast moving glass fiber freshly drawn from the heated silica preform in the furnace. Since the air is entrained unavoidably when the glass fiber passes through the cooling unit, the helium is needed to be injected constantly into the cooling unit. The present numerical study investigates and analyzes the air entrainment using an axisymmetric geometry of glass fiber cooling unit. The effects of helium injection rate and direction on the air entrainment rate are discussed in terms of helium purity of cooling gas inside the cooling unit. For a given rate of helium injection, it is found that there exists a certain drawing speed that results in sudden increase in the air entrainment rate, which leads to the decreasing helium purity and therefore the cooling performance of the glass fiber cooling unit. Also, the helium injection in aiding direction is found to be more advantageous than the injection in opposing direction.

헬륨가스 주입식 유리섬유 냉각장치의 냉각성능 해석 (COMPUTATIONAL ANALYSIS ON THE COOLING PERFORMANCE OF GLASS FIBER COOLING UNIT WITH HELIUM GAS INJECTION)

  • 오일석;김동주;우마로프 알리세르;곽호상;김경진
    • 한국전산유체공학회지
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    • 제16권4호
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    • pp.110-115
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    • 2011
  • A modern optical fiber manufacturing process requires the sufficient cooling of glass fibers freshly drawn from the heated and softened silica preform in the furnace, since the inadequately cooled glass fibers are known to cause improper polymer resin coating on the fiber surface and to adversely affect the product quality of optical fibers. In order to greatly enhance the fiber cooling effectiveness at increasingly high fiber drawing speed, it is necessary to use a dedicated glass fiber cooling unit with helium gas injection between glass fiber drawing and coating processes. The present numerical study features a series of three-dimensional flow and heat transfer computations on the cooling gas and the fast moving glass fiber to analyze the cooling performance of glass fiber cooling unit, in which the helium is supplied through the discretely located rectangular injection holes. The air entrainment into the cooling unit at the fiber inlet is also included in the computational model and it is found to be critical in determining the helium purity in the cooling gas and the cooling effectiveness on glass fiber. The effects of fiber drawing speed and helium injection rate on the helium purity decrease by air entrainment and the glass fiber cooling are also investigated and discussed.

광섬유 냉각장치의 헬륨 주입기 설계를 위한 전산열유동해석 (Computational Thermo-Fluid Analysis for the Effects of Helium Injection Methods on Glass Fiber Cooling Process in an Optical Fiber Manufacturing System)

  • 박신;김경진;김동주;박준영;곽호상
    • 한국기계가공학회지
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    • 제13권2호
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    • pp.124-130
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    • 2014
  • In a mass manufacturing system of optical fibers, the sufficient cooling of glass fibers freshly drawn from a draw furnace is essential, asinadequately cooled glass fibers can lead to poor resin coating on the fiber surface and possibly fiber breakage during the process. In order to improve fiber cooling at a high drawing speed, it is common to use a helium injection into a glass fiber cooling unit in spite of the high cost of the helium supply. The present numerical analysis carried out three-dimensional thermo-fluid computations of the cooling gas flow and heat transfer on moving glass fiber to determine the cooling performance of glass fiber cooling depending on the method of helium injection. The results showed that afront injection of helium is most effective compared to a uniform or rear injection for reducing air entrainment into the unit and thus cooling the glass fibers at a high fiber drawing speed. However, above a certain amount of injected helium, there was no more increase of the cooling effect regardless of the helium injection method.