• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.34-35
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• 2015

Recently, introduction of Advanced water treatment facilities has been increasing due to serious domestic water pollution. Ozone is a strong oxidizing materials in the advanced water treatment facilities. However, due to such a strong oxidation, Ozone eroded waterproofing/corrosion on the concrete surface and caused performance degradation. Therefore, in this study, permeability experiment of metal spraying system by concrete surface treatment was conducted.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2002.05a
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• pp.154-162
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• 2002

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.1
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• pp.87-94
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• 2003

Recently, LPLi(Liquied-Phase LPG injection) system is studied for the new stringent emission regulations. But , there are some problems to be solved such as injector tip icing and fuel leakage for LPLi system development. In this paper, the icing problem near injector tip which leads to difficulty of accurate A/F control was studied and reported. Icing of injector tip and port wall was observed at all the cases in this study regardless of injection duration and angle, air humidity change. The spray angle of LPLi was observed approximately two times wider than that of Gasoline injection. This makes the LPLi spray collide with intake port around injector tip. Temperature of the wetted area was decreased and icing of water vapor contained in intake air because of evaporation of the fuel film. The ice of the injector tip and port wall is also affected by the materials related to heat transfer.

• 한국연소학회:학술대회논문집
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• 2005.10a
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• pp.93-96
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• 2005

High temperature furnace such as Steam power plant and incinerator contribute considerable part of NOx generation and face urgent demand of De-NOx system. Reducing agents are necessary to use De-NOx system. In this study mixing caused by direct injection of reducing agent solution spray into flue gas duct was measured. Carbonated water was used as tracer and simulated agent because ammonia as a reducing agent is not proper to experiment. Mixing and evaporation must occur simultaneously and quickly enough to achieve desirable efficiency. To achieve that, the angle of attack of static mixer and the location is simulated and $CO_2$ concentration is measured.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.47-53
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• 2006

The oxidizer-rich preburner is applied to the high efficiency closed cycle rocket propulsion system. This system is generally operated on oxidizer-fuel mixture ratio over than 50. The spray quality and mixing performance are very important for safe combustion of this preburner. This paper presents basic concept and spray characteristic of the preburner injector.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2002.05a
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• pp.61-65
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• 2002

The present study was numerically and experimentally performed to investigate the fire suppression performance of water mist spray subjected to thermal radiation in closed space. Downward-directed water mist sprays to interact with an under kerosine pool fire were investigated in test facility. The mass mean diameters of water mist droplet were measured by PMAS under various flow conditions. The developed water mist spray nozzle was satisfied to the criteria of NFPA 750, Class 1. The mechanism of the fire suppression by water mist was concluded to be cooling of the fire surface which lead to suppressed of fuel evaporation. It was proved that the water mist spray system under lower pressures could be applied to underground fire protection system.

• Journal of Power System Engineering
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• v.10 no.2
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• pp.111-116
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• 2006

Tribologcal property of the ceramics used in severe condition was investigated and both $Al_2O_3$ ball and Al/SiC composite made by thermal spray process[TSP] were used as a specimen in this study. Four kinds of material couple in ball and disk specimens were tested in the dry condition by using ball-on-disk type tribo-tester. Friction coefficient, surface roughness, wear rate, and photograph of the worn surface were investigated. Generally, High SiC contents[$40{\sim}50%$] specimens showed very low friction coefficient below 0.05 and little wear rate in dry condition. And also, low SiC contents[0%] specimens showed a moderate wear rate and high coefficient of friction at the same condition.

• Journal of Power System Engineering
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• v.14 no.2
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• pp.5-11
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• 2010

분사연료의 혼합기형성과정 최적화를 통한 연소제어 기술은 디젤기관의 기관운전 및 배기특성을 향상시키기 위하여 매우 중요하다. 또한 분무의 혼합기형성 최적화를 위해서는 분사된 연료와 주위기체와의 혼합과정에 영향을 미치는 분무내부의 유동특성에 대한 연구는 필수 불가결하다. 따라서 본 연구에서는 고온 고압의 증발장에서 분무의 액상 거동에 주목하고, 그 거동특성을 통하여 증발디젤분무의 혼합기형성을 해석한다. 비정상 증발분무의 중심축에 레이저 시트광을 입사한 후, 액상분무 액적의 Mie 산란광에 의한 2차원 화상을 획득하여 증발분무 액상의 속도분포 및 와도(vorticity) 등을 구하였다. 분무의 속도분포 및 와도는 2차원 화상에 PIV법을 적용하여 계산하였다. 그림 1에 본 연구에서 구한 속도분포의 일례를 보인다. 본 연구의 결과로 상변화를 동반하는 비정상 증발장에서 구한 분무액상의 거동 특성은 상변화가 일어나지 않는 비증발장에 있어서의 분무거동특성과 유사함을 확인하였다.

• Journal of Power System Engineering
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• v.14 no.2
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• pp.16-21
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• 2010

분사된 연료의 미립화(atomization), 증발(evaporation), 그리고 혼합기형성과정(mixture formation process)이 디젤엔진의 착화 및 연소특성에 영향을 미치기 때문에, 디젤엔진 내에 분사된 연료의 구조해석으로부터 일련의 과정, 즉 고압분사, 분열(breakup), 미립화, 그리고 주위기체의 난류 도입(entrainment)에 관한 연구$^{1-3)}$는 꾸준히 행해져왔다. 본 연구는 증발디젤분무의 구조해석으로부터 디젤충돌분무의 혼합기형성과정을 조사한다. 주위기체의 밀도는 실험변수로서 선택하였고, $5.0kg/m^3$에서 $12.3kg/m^3$까지 변화시켰다. 그리고 소형고속디젤엔진에 있어서 연료분사초기의 상태의 고온 고압 설정이 가능한 정적용기를 사용했다. 주위 온도와 연료분사압력은 각각 700K 및 72MPa로 일정하게 유지했다. 충동증발분무의 액상과 기상의 이미지는 엑시플렉스형광법으로 동시 계측하였다. 실험결과로서 주위기체의 밀도가 높을수록 충돌분무의 선단도 달거리가 주위기체의 항력으로 인하여 감소하였다.

• IE interfaces
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• v.3 no.2
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• pp.23-38
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• 1990

The use of robots for painting operations is a powerful alternative as a means for automation and quality improvement. A typical method being used for motion planning of the painting robot is to guide the robot along the desired path : the "lead-through" method. Although this method is simple and has been widely used, it has several drawbacks a) The robot cannot be used during the teaching period, b) A human is exposed to a hostile environment, c) The motions taught are, at best, human's skill level. To deal with the above problems, an integrated robot-trajectory planning scheme is presented. The new scheme takes CAD data describing the shape and geometry of the objects, and outputs an optimal trajectory in the sense of coating thickness and painting time. The purpose of this paper is to investigate theoretical backgrounds for such a scheme including geometric modeling, painting mechanics and robot trajectory planning, and develop algorithms for generating spray gun paths and minimum-time robot trajectories. Future study is to implement these algorithms on an workstation to develop an integrated software system ; ATPS(Automatic Trajectory Planning System) for spray painting robots.