• 대한기계학회논문집A
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• 제24권9호
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• pp.2159-2166
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• 2000

Recently, high performance machining center requires special type of sealing mechanism that prevent a leakage of oil jet or oil mist lubrication system. Sealing of oil-air mixture plays important r oles to have an enhanced lubrication for performance machining center. Current work emphasizes on investigations of the air jet effect on the protective collar type labyrinth seal. To improve sealing capabilities of conventional labyrinth seals, air jet is injected against the leakage flow. In this study, an adapted model is introduced to improve sealing capability of conventional non-contact type seals. It has a combined geometry of a protective collar type and an air jet type. Both of a numerical analysis by CFD (Computational Fluid Dynamics) and experimental measurements are carried out to verify sealing improvement. The sealing effects of the leakage clearance and the air jet magnitude aic studied in various parameters. Gas or liquid has been used as a working fluid for most of nori-contact types seals including the labyrinth seal. However, it is more reasonable to regard two-phase flows because oil mist or oil jet are used for high performance spindle's lubrication. In this study, working fluid is regarded as two phases that are mixed flow of oil and air phase. Both of turbulence and compressible flow model are also introduced in a CFD analysis to represent an isentropic process. Estimation of non-leaking property is determined by amount of pressure drop in the leakage path. Results of pressure drop in the experiment match reasonably to those of the simulation by introducing a flow coefficient. Effect of the sealing improvement is explained as decreasing of leakage clearance by air jetting. Thus, sealing effect is improved by amount of air jetting even though clearance becomes larger

• 한국화재소방학회논문지
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• 제23권6호
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• pp.57-65
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• 2009

미분무 소화시스템을 이용하여 철도차량 내부 화재진압 실험을 수행하였다. 실험차량은 실물 철도차량이며, 화재시나리오는 표면화재 1종, 유류화재 1종, 그리고 미분무 소화시스템에 의한 화재 공간 내의 공간 냉각 능력을 조사하기 위한 차폐화재 1종 등 총 3종이었다. 실험에 사용된 소화시스템은 6종으로, 일정압력을 가지는 소화시스템 5종, 질소가압 압력용기로부터 분사되는 소화시스템 1종이다. 실험 결과 미분무 소화시스템이 철도 차량 내부의 화재를 효과적으로 소화시키거나, 소화가 되지 않더라도 우수한 공간 냉각 능력으로 화재 피해를 최소화할 수 있음을 알았다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.32-37
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• 2002

High speed machining is one of most effective technologies to improve productivity. It can give great advantage for manufacture of die and Moulds. However, when the high speed machining of materials, especially in machining of micro groove, a severely thermal demage was generated on workpiece and tool. Generally, the cutting fluid is used to improve penetration, lubrication, and cooling effect. In order to rise the performance of lubrication, it contains extreme pressure agents (Cl, S, P). But the environment of work room go bad by those additive Therefore, the compressed chilly air with Oil mist system was developed to replace the conventional cutting fluid system. This paper carried out the tests to evaluate the machinability by the cutting environment in high speed micro groove machining of NAK80 (HRC40). Compressed chilly air with oil mist was ejected on the contact area between cutting edge and workpiece. The effectiveness of this developed compressed chilly air with oil mist system was evaluated in terms of tool life. The results showed that the tool life of carbide tool coated TiAIN with compressed chilly air mist cooling was much longer than with dry and flood coolant when cutting the material.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.172-175
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• 2002

High speed machining is one of the most effective technologies to improve productivity. It can give great advantage for manufacture of die and Moulds. However, when machining of micro groove in high speed machining a severely thermal damage was generated on workpiece and cutting tool. Generally, the cutting fluid is used to improve penetration. lubrication. and cooling effect. In order to rise the performance of lubrication. it contains extreme pressure agents (Cl, S, P). But the environment of work room go bad by those additive. Therefore, the compressed chilly air with oil mist system was developed to replace the conventional cutting fluid system. This paper carried out the tests to evaluate the machinability by the cutting environment in high speed micro groove machining of NAK80 (HrC40). Compressed chilly air with oil mist was ejected on the contact area between cutting edge and workpiece. The effect of this developed compressed chilly air with oil mist system was evaluated in terms of tool life. The results showed that the tool lift of carbide tool coated TiAlN with compressed chilly air mist cooling was much longer than that of the dry and flood coolant when cutting the material.

• 한국기계가공학회지
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• 제15권5호
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• pp.117-124
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• 2016

In this paper, we developed a breather valve with a water mist system for use near an oil storage tank. Our process applied a water mist system to the flame arrester to evaluate the fire suppression characteristics. For the fire suppression evaluation of the water mist system, we evaluated the angle of the nozzle, fire suppression, spray particle size, flashback, fire suppression time, and fire suppression test of antifreeze. Through the fire suppression test, the best fire suppression nozzle used an angle of $140^{\circ}$, and the flashback phenomenon of flame arrester did not occur. The fire suppression time of water mist system time was within three seconds, and the antifreeze was no problem with the fire suppression.

• 한국재난정보학회 논문집
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• 제16권4호
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• pp.627-637
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• 2020

연구목적: 랙크식 창고의 대표적 가연물인 CEP에 대하여 미분무 소화설비의 적용성을 알아보기 위하여 본 실험적 연구를 수행하였다. 연구방법:먼저 본 실험에 사용된 미분무수 소화설비가 유류화재 소화가 가능한지 확인을 수행하였다. 그 후, CEP 박스를 유류화재실험과 동일한 소규모 공간에 적재한 후, 개구부의 열림 및 닫힘, 그리고 닫힘 상태에서의 내부 적재물을 증가시키는 3가지 시나리오를 대상으로 실험을 수행하였다. 시나리오는 미분무수 소화에 중요한 영향요소인 개구부와 공간크기조건을 고려하여 설정되었다. 연구결과:유류화재에 대한 소화시험에서는 문의 열림과 닫힘 상태, 모두에서 화재가 잘 진압되는 것으로 나타났다. 동일 공간조건에서 CEP 가연물의 화재 시 개구부의 열림 상태에서는 화재가 진압되지 않았다. 개구부를 닫은 경우 화재는 진압되었지만, 일부 잔염이 확인되었다. 결론: 유류화재 진압실험에서 미분무수 소화설비가 개구부 열림과 닫힘 상황 모두에서 유효한 소화능력을 보여주었다. 하지만 CEP화재에 대해서는 닫힘 상태에서만 유효한 소화능력을 보여주었으며, 재 발화의 가능성이 있음이 나타났다.

• 월간산업보건
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• 통권231호
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• pp.15-18
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• 2007

• 월간산업보건
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• 통권229호
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• pp.14-16
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• 2007

• 월간산업보건
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• 통권230호
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• pp.18-21
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• 2007

• Journal of Advanced Marine Engineering and Technology
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• 제38권7호
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• pp.834-843
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• 2014

본 연구에서는 마이크로 탄소 브러쉬 하전부와 평판형 금속 집진부로 구성된 저전력 소비형 2단형 전기집진기를 개발하였고, 특히 인체 위해성이 높은 $0.3{\mu}m$급의 미세한 오일 미스트에 대한 인가전압 및 소비전력별 집진효율 특성을 실험연구를 통해 고찰하였다. 하전부의 인가전압에 따른 단위 입자당 하전율과 입경별 집진효율을 측정함과 동시에 이론에 근거한 계산값과 비교해 보았으며, 9 주 동안의 장시간 운전을 통해 지속적으로 포집된 오일 미스트에 의한 전기집진기의 성능을 열유체역학적인 관점에서 변화를 조사하였다.