• 한국생산제조학회지
• /
• 제8권2호
• /
• pp.50-55
• /
• 1999

The exhaust emissions from diesel vehicle are known to be harmful to human health and environment. Recently, one of the most environment problems is particulate matter. In this study, through the actual exper iment and heat transfer of exhaust pipe in light duty diesel engine equipped with the ceramic filter trap of throttling type, following results are obtained. 1. In case of light duty diesel engine equipped with ceramic filter trap of throttling type, Power and torque of engine were decreased about 5%, compared with the case without trap system. It means that was not so much effect on base engine performance.2. If the length of exhaust pipe when equipping with ceramic filter trap is suitably controlled, the range of regeneration will be expand much more.3. Particulate matter reduction efficiency of ceramic filter trap system was about 70%-80%, so it was proved a good system to reduce particulate matter.In experiment, test was conducted to estimate engine emission in 2,476cc light duty diesel engine which was equipped with ceramic filter trap.

• 한국시뮬레이션학회논문지
• /
• 제14권4호
• /
• pp.69-76
• /
• 2005

To investigate the characteristics of the sound-pipe on the top of King Song-Dok bell, using computer simulation, the throat impedance was evaluated for the straight pipe and conical pipes with varying taper angles. When sound propagates in a rigid walled, unflanged circular pipe with wavelength larger than radius, the acoustic motion is planar, much as in a bar. The incident sound waves are reflected at the end of pipe and some of them are transmitted. The reflection coefficient and radiation impedance of the sound-pipe of King Song-Dok bell were calculated, and the results demonstrated that the high frequency sound is radiated through the sound-pipe. It behaves like a frequency filter.

• 한국농공학회논문집
• /
• 제57권3호
• /
• pp.87-92
• /
• 2015

Cultivation on reclaimed tidal land is often difficult in the problem such as high salinity of soil, bad drainage because of high level of groundwater. Many researches have been made efforts to solve these problems, but effect of improvement is low and practicality is insufficient. In this study, through numerical analysis of the transport properties of salt and water, we suggested underground drainage of the reclaimed land and the desalination promotion methods in the soil. The results of characteristic of desalination and seepage analysis of underdrain show that underdrain is able to increase twice of the underground seepage amount when installing perforated pipe with horizontal filter (width 50cm) more than installing only the perforated pipe. For soil which coefficient of permeability is below $1{\times}10^{-4}cm/s$ that desalination with pond water is not possible, a method to increase the permeability of the soil is necessary. Therefore, it was concluded that application of underdrain using perforated pipe with horizontal filter would be low-cost and practical.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2008년도 춘계학술대회논문집
• /
• pp.634-637
• /
• 2008

A large eddy simulation with an explicit filter on unstructured mesh is presented. The flow filed is semi-implicitly marched by a fractional step method. Spatial discretization of the solver is designed to guarantee the second order accuracy. An isotropic explicit filter is adopted for measuring the level of subgrid scale velocity fluctuation. The filter is linearity-preserving and has second order commutation error. The developed subgrid scale model is basically eddy viscosity model which depends on the explicitly filtered fields and needs no additional ad hoc wall treatment, such as van Driest damping function. For the validation, the flows in a channel and a pipe are calculated and compared to experimental data and numerical results in the literature.

• 한국농공학회지
• /
• 제14권2호
• /
• pp.2593-2602
• /
• 1972

Plastic pipes Wrapped with synthetic filter are recently used for drainage or Collecting of Underground water. But it's use is possible only for small size of diameter less than 300mm, because large size plastic pipes are not readily availabe. For large diameter infiltration gallery, porous concrete pipes are now used, but it's heavy weight brings difficulties in making, moving and setting of the pipes. With it's conventional method of filter setting, fine sands are brought into the pipes to make trouble to lifting pumps and channels Therefore, initial construction cost and maintenance cost become high. To solve-this problem, new method is developed and tested. Small PVC pipes(diameter 14mm) are assembled at the site of construction to newly devised I beam type circls. The size of circular inpiltration gallery is optionally determined by I beam type circle which support small PVC pipes and is made of PVC amterial. This gallery are wrappd with syntheitc filter to prevent sand instruction. In this test, the diameter of 300, 400, 500mm were used. I beam type circles were made with PVC plated with thickness. t=6, 9, 12mm. Water quantity collected through the PVC circulor gallery are measured and the strengths of the gallery. 1. Allowable setting depth of gallery pipe below graund for the case of t=6mm, D=500mm is 2.72m. 2. Collected water quantity depends on soil texture, depth of water grandient of water surface, filter material angle of setting etc. 3. About 126% of water quantity collected from the one gallery pipe measured in two gallery pipes of two parallel installation.

• 한국화재소방학회논문지
• /
• 제31권1호
• /
• pp.89-97
• /
• 2017

본 연구에서는 서비스센터에서 정비를 받고 출고한 날로부터 5일 후 터널 주행 중에 발생한 디젤승용차 화재 사례를 조사분석하였다. 조사분석한 결과, 배기구 내부에 흰색 이물질이 다량 부착되어 있었고, 배기관의 중간에 설치된 diesel particulate filter (DPF) 위쪽의 차열재가 용융 및 소실되어 있었고, DPF 위쪽의 차실 내부 금속재 바닥이 천공되어 금속재 바닥 위에 놓인 고무매트가 연소된 케이스이었다. 그리고 DPF 앞쪽의 배기관에는 과열흔적이 없고 DPF부터 배기구까지의 배기관에 과열흔적이 있는 특이점이 있었다. 이러한 특이점들은 DPF가 과열되고 DPF에서 발화된 경우에만 나타나므로 이 승용차화재는 DPF 내부 과열에 의해 발생한 것으로 분석할 수 있었다. 그리고 이 승용차화재조사를 통해 디젤승용차 화재원인조사 과정에서 배기구 내부에서 흰색 이물질이 확인되는 경우에는 DPF를 분리하여 DPF 내부의 손상을 조사하여 화재원인을 판정하여야 함을 알 수 있었다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
• /
• pp.917-922
• /
• 1992

Resently there have been increasing interests in adaptive identification and control of flexible structures. In this paper, vector channel lattice filters and their applications to parameter identification of flexible structures are studied. Numerical examples are given to show its performace to estimate the natural frequencies of 5-mass system. It is observed that vector channel lattice filter convetges quickly and identifies modal frequencies even when some of them is unobservable for some measurements. Experimental results demonstrated the ability of the lattice filter to identify the natural frequencies and the damping ratios of cantilever beam and pipe.

• Journal of Advanced Marine Engineering and Technology
• /
• 제36권1호
• /
• pp.109-117
• /
• 2012

본 논문은 매연여과장치(DPF)의 Inlet Pipe 길이를 5가지 경우로 변화시켜, 이 변화가 유동장에 미치는 영향을 살펴보았다. 실험 방법으로서는 PIV 계측과 상용코드를 사용하여 수치해석을 수행 하였으며, 그 결과 PIV와 CFD는 87%로 일치하는 상관성을 보였다. 또한 동일한 유속 조건일 때 Inlet Pipe 길이가 20mm일 때 안정적이고 높은 압력 값을 보여 매연여과율을 높일 수 있을 거라 사료된다.

• 소음진동
• /
• 제4권3호
• /
• pp.337-343
• /
• 1994

A method of the leak detection from the pipe system by using accelerometer is proposed. The signal detected from accelerometer is proved experimentally to be a dispersive wave. Based on the experiments, a method using the narrow band pass filter and the unit impulse response function is analyzed. The method uses the characteristics of the unit impulse response function, that the function is available evenin the narrow band signal because, unlike the cross correlation, it is normalized by the auto spectrum. The accelerometer is quite easier to use than the hydrophone in adapting to the pipe system.

• 한국수자원학회논문집
• /
• 제50권8호
• /
• pp.579-586
• /
• 2017

기능성 스크린이 부착된 집수관의 정량적인 취수량을 분석하고, 여과 재료를 통한 부유물질 및 탁도의 개선효과를 알아보기 위해 네 단계의 연구방법을 제시하였다. 첫 번째 단계에서는 소규모의 실험장치를 구성하여 실증 플랜트 여과 재료의 구성 방법을 결정하였고, 두 번째 단계에서는 견본 장치를 구성하여 기능성 스크린이 장착된 집수관을 통해 유량 값을 측정하였다. 세 번째 단계에서는 각각의 여과 재료에 대해서 탁도의 상태를 달리하여 유량을 측정하고, MODFLOW를 이용하여 투수계수를 추정하였다. 마지막으로 견본 장치를 MODFLOW로 수치모델을 구성하여 세 번째 단계에서 추정된 투수계수를 각각 적용하고 취수량을 분석하였다. 0 NTU일 때 추정된 투수계수 적용 결과 실제 관측 유량에 비해 모델링 결과는 39.96% 높게 나타났다. 이에 비해 100~120 NTU일 때 추정된 투수계수 적용 결과 유량의 차이는 9.41% 높게 나타났다.