• Proceedings of the KAIS Fall Conference
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• 2007.11a
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• pp.312-314
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• 2007

본 논문에서는 비데용 물 분사 노즐의 내부유동을 가시화하기 위해서 여러 가지 설계변수에 관한 연구가 수행되었다. 특히 물 분사에 만 의존했던 과거의 세정시스템과는 달리 물과 공기를 혼합해서 물도 절약하고 세정의 효과도 높이고자 하는 기술을 개발하고자 했다. 상용코드인 CFD-ACE+를 이용하여 내부유동 특성을 관찰했고 여러 가지 인체 공학적인 설계가 되도록 다양한 각도에서 검토되었다.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.6
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• pp.628-636
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• 2005

In this paper. the effects of a WI(Water Injection) in the intake pipe for a 4-cylinder Dl(Direct Injection) diesel engine are investigated experimentally, The WI system was controlled by the duty cycle from the intake manifold's temperature and MAF(Manifold Air Flow) First. effect of EGR on NOx reduction was investigated. Then WI system was applied to reduce NOx As the results. we can make the NOx map and visualize the NOx results by variation of engine speed and engine load It was known that effect of WI system on NOx reduction without the EGR was better than the with EGR base engine except of low load and speed condition.

• Journal of the Society of Naval Architects of Korea
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• v.34 no.4
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• pp.21-30
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• 1997

This paper describes the experimental method of a pod-type waterjet propulsion system in a towing tank and shows the experimental analysis and test results of a designed waterjet propulsion system to be used for a hybrid high speed craft. The cruising performance of this craft is estimated from the results of the hull resistance test and waterjet test under the assumption that the interaction between the hull and the inlet pod is very small. A pod-type waterjet system with an axial pump was designed and a stand-alone waterjet experimental system was developed. Useful data such as the pump performance, the jet efficiency, the losses of inlet duct and nozzle were obtained. Test results show a good agreement with the design requirement.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.192.1-192.1
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• 2016

최근 들어, 열악한 실내 공기 환경과 미세 먼지의 유입으로 아토피 피부염, 알레르기성 비염 및 천식 등의 감염성 질환이 증가하고 있다. 따라서, 공기 중 병원균(Airborne pathogens)을 친환경적으로 제거하는 기술이 요구되고 있는 추세이다. 본 연구에서 제안하는 시스템은 물을 이용하여 플라즈마를 발생시키는 시스템이다. 기존 플라즈마를 이용한 공기 정화 장치는 공기를 사용하여 플라즈마를 발생시키므로 오존과 같은 인체에 유해한 물질들이 발생되는 문제점이 있다. 하지만, 본 연구에서는 물을 사용하여 플라즈마를 발생시키므로 활성 라디칼들이 포함된 물을 미스트 형태로 분사하여 인체에 무해하며, 대기 중 병원균 살균이 가능한 장점이 있다. 물 플라즈마 젯 분사장치는 전원 공급 장치, 플라즈마 전극 그리고 플라즈마 노즐로 이루어져 있으며 주입되는 물을 기반으로 플라즈마를 발생시킨다. 장치의 특성을 분석하기 위하여, 오실로스코프로 전압 및 전류를 측정하였고 적정법을 이용하여 생성되는 활성 라디칼들의 농도를 측정하였다. 또한 살균 능력을 평가하기 위하여 병원균 중 대표적으로 대장균을 배양하여 살균 실험을 수행하였으며, 결과적으로 90% 이상의 대장균이 사멸하는 것을 확인하였다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.5
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• pp.113-121
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• 2013

The road icing forecast and snow detection system using state evaluation algorithm of multi sensor optimizes snow melting system to control spread time and amount of chemical spread application This system operates integrated of contact/non-contact sensor and infrared camera. The state evaluation algorithm of the system evaluates road freezing danger condition and snowfall condition (snowfall intensity also) using acquired data such as temperature/humidity, moisture detection and result of image signal processing from field video footage. In the field experiment, it proved excellent and reliable evaluated result of snowfall state detection rate of 89% and wet state detection rate of 94%.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.05a
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• pp.240-243
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• 2001

괘도차량에 부착된 물분사추진기의 유동해석을 실험과 포텐셜해석 그리고 점성해석을 사용하여 그 결과를 비교하였다. 예인수조에서 여러 차량 전진속도에 대해서 임펠러 회전수를 조정하여 제트속도를 변화시키면서 덕트표면에서의 정압을 계측하였다. 이는 제트시스템의 효율을 추정하기 위함이고 관로를 통한 에너지분포를 알 수 있다. 점성유동해석을 위해 지배방정식은 비압축성 Navier-Stokes 방정식을 유한체적법을 사용하여 이산화하고 해석하였으며 난류영향은 표준 ĸ-$\varepsilon$난류모형을 사용하여 유동을 해석하고 실험결과 및 포텐셜 해석결과와 비교하였다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.5
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• pp.130-135
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• 2013

Anti-icing system can reduce traffic accidents and congestion by quickly removing the frozen road surface area. there is no decision criteria for determining application of the Anti-icing system in Korea. In this study, we proposed the decision criteria for determining application of the anti-icing system based on weather and road conditions, i.e., geometric and topographic conditions. Regional climate survey, Solar Radiation analysis, and dynamic vehicle simulation considered road geometry was conducted to standardize the installation method of anti-icing system. Also, we have developed a software that can be determined an installation of anti-icing system.

• Fire Science and Engineering
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• v.28 no.6
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• pp.47-51
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• 2014

In this study we investigated the risk of electric shock and the possibility of current flow from the sprayed water when fire took place in a photovoltaic (PV) installed building. The sprayed water was analysed by using a mathematical model, a water spray system for water conductivity was made. With changing the initial water flow rate the water resistance was measured, and compared with the numerically expected value. As the experimental and numerical computing result, we were able to define the requirements that must be considered in the fire of PV systems.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.1
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• pp.25-32
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• 1999

This study was carried out to reduce NOx emissions from diesel engine and to investigate the variation of engine performance using the water injection. In this study the water was extracted from the exhaust gas and injected directly into the intake port with the inlet charge. The water condensing system operated as a closed system without any supplementary water supply. The experimental parameters such as the revolution the torque and the water injection rate are varied and the result from this experiment found the significant NOx reduction whereas the smoke emission increases as water/air ratio increases as the cases like the EGR. In spite of increasing the quantity of the water injection the engine output was slightly decreased and the specific fuel consumption was increased as was anticipated. Especially the system was founded to be effective on the reduction of the NOx emissions at the high load region relatively.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.11
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• pp.999-1004
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• 2010

Recently, many technologies have been developed in order to satisfy stringent emission regulations. However, in the case of diesel engines, the stringent emission regulations with respect to NOx and PM have not yet been satisfied. A dramatic reduction in the NOx and PM emissions could be achieved by using after-treatment systems such as lean NOx trap (LNT) and urea-SCR systems. However, the high temperature in the exhaust pipe affects the spray behavior of the secondary injector, which is used for supplying the Urea-SCR. Because of this high temperature, it is difficult to achieve uniform distribution of the reducing agent in the manifold. In this paper, the characteristics of a urea-SCR injector used for injecting in the exhaust pipe are presented. The purpose of this study was to investigate the spray characteristics of the injector, such as the spray angle, injection quantity, and SMD. In addition, laser diagnostics and high-speed-camera images were used to analyze the injector spray characteristics and to present a distribution of reduction in the transparent manifold.