• 자원리싸이클링
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• 제23권6호
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• pp.30-39
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• 2014

코로나 방전 정전선별기 내에서 인쇄회로기판(Printed Circuit Board, PCB) 분쇄 입자의 이동궤도를 전산 모사하였다. 여기서 PCB입자는 전자부품 분리된 기판을 파쇄한 것으로, 대부분 구리와 FR-4(Flame Retardant Level-4)로 이루어져있다. 우선 입자가 선별기내 회전전극으로부터 탈착 지점을 계산하였으며, 중력, 원심력, 정전기력의 평형으로부터 유도되었다. 한편 탈착 후 이동궤도는 입자의 운동방정식으로부터 구한 가속도를 시간 적분하여 계산하였다. 시뮬레이션 변수는 입자의 크기, 공급전압의 세기, 회전전극속도 및 유도전극 각도로 하였다. 입자 이동궤도에 미치는 영향은 구리 입자의 경우에는 회전속도가 주요 변수였으나, 반면 FR-4 입자의 경우에는 상기 모든 변수에 영향을 받는 것으로 나타났다.

• 조명전기설비학회논문지
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• 제19권1호
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• pp.44-51
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• 2005

본 연구에서는 구-구갭을 수평 배치하였을 때, 연소화염에 의한 교류 및 직류 플래시오버전압 특성을 조사하였다. 화염에 의한 플래시오버 극성을 조사하기 위해 전압 및 전류파형을 측정하였으며, 플래시오버가 발생되기 전에 쿨롱력에 의한 화염의 형상 변화를 관찰하였다. 또한 플래시오버 전압의 저하 요인으로서 상대공기밀도의 저하 및 연소화염의 열전리 영향에 대해 고찰하였다. 실험 결과, 구-구갭에서 접지측 전극과 갭길이의 비를 k라고 할 때, 화염위치 k:0(접지측), k=0.5(중앙부) 및 k=1.0(전원측)인 경우 화염에 의한 교류 섬락전압의 평균값은 화염이 없을 때에 비해 각각 79.9, 82.9 및 $87.5[\%]$ 저하되었으며, 또한 화염의 높이 h=0, h=5 및 h=9[cm]일 때 교류 플래시오버 전압의 평균값은 화염이 없는 경우를 기준으로 하였을 때 각각 85.0, 40.8 및 $28.2[\%]$ 저하되었다. 소규모 연소화염에서의 열전리 영향은 크지 않는 것으로 나타났다.

• 한국분무공학회지
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• 제8권3호
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• pp.33-40
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• 2003

The low-emission and high-performance diesel combustion is an important issue in the combustion research community, In order to understand the detailed diesel flame involving the complex physical processes, it is quite desirable to diesel spray dynamics, auto-ignition and spray flame propagation. Dynamics of fuel spray is a crucial element for air-fuel mixture formation, flame stabilization and pollutant formation, In the present study, the diesel RCM (Rapid Compression Machine) and the Electric Control injection system have been designed and developed to investigate the effects of injection pressure, injection timing, and intake air temperature on spray dynamics and diesel combustion processes, In terms of the macroscopic spray combustion characteristics, it is observed that the fuel jet atomization and the droplet breakup processes become much faster by increasing the injection pressure and the spray angle, With increasing the cylinder pressure, there is a tendency that the of spray pattern in the downstream region tends to be spherical due to the increase of air density and the corresponding drag force, Effects of intake temperature and injection pressure on auto-ignition is experimently analysed and discussed in detail.

• 대한기계학회논문집B
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• 제33권5호
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• pp.343-348
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• 2009

The present study has experimentally investigated the effects of $CO_2$ diluted oxygen on the structure of swirl-stabilized flame in a lab-scale combustor. The methane fuel and oxidant mixture gas ($CO_2$ and $O_2$) were mixed in a pre-mixer and introduced to the combustor through different degrees of swirl vanes. The flame characteristics were examined for various amount of carbon dioxide addition to the methane fuel and various swirl strengths. The effects of carbon dioxide addition and swirl intensity on the combustion characteristics of pre-mixed methane flames were examined using chemiluminescence techniques to provide information about flow field. The results show that the hot combustion zone increases at the upstream reaction zone because of an increase in the recirculation flow for an increase in swirl intensity. The hot combustion zone is also increased at the downstream zone by recirculation flow because of an increase in swirl intensity which results in higher centrifugal force. The OH and CH radical intensities of reaction zone decrease with carbon dioxide addition because the carbon dioxide plays a role of diluted gas in the reaction zone.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.447-452
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• 2000

The low-emission and high-performance diesel combustion is an important issue in the combustion research community. In order to understand the detailed diesel flame field involving the complex Physical Processes, It Is quite desirable to study diesel spray dynamics, auto-ignition and spray flame propagation. Dynamics of fuel spray is a crucial element for air-fuel mixture formation flame stabilization and pollutant formation. In the present study, the diesel RCM (Rapid Compression Machine) and the Electric Control injection system have been designed and developed to investigate the effects of injection Pressure, injection timing, and intake air temperature on spray dynamics and diesel combustion processes. In terms of the macroscopic spray combustion characteristics it is observed that the fuel jet atomization and the droplet breakup processes become much faster by increasing the injection pressure and the spray angle. With increasing the cylinder pressure there is a tendency that the shape of spray pattern in the downstream region tends to be spherical due to the increase of air density and the corresponding drag force. Effects of intake temperature and injection pressure on auto-ignition is experimently analysed and discussed in detail.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.365-369
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• 2004

The Advantages of hot machining are the reduction of cutting forces, tool wear, and the increase of material removal rates. In this study, a hot-machining using gas flame heating characteristics of milling by CBN tip was analyzed, and the influence of the surface temperature and the depth of cut on the tool life were investigated. The results show that hot machining of tungsten carbide-alloyed is more effective than conventional machining. In addition, some advantages obtained from hot machining, such as decrease of tool wear and cutting force, high surface quality.

• 대한기계학회논문집B
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• 제27권1호
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• pp.46-53
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• 2003

Effects of electric force on the morphology and growth of aggregates were studied experimentally. Nano-sized NaCl particles were supplied to a flame to perform the unipolar charging state. This electric precursor did not modify a temperature profile of the flame. The morphology of aggregates was measured by TEM image processing technique and the light scattering technique. In the unipolar charged state, the fractal dimension of aggregates was smaller than that of' the electrically neutral state. This result was in good agreement with our previous numerical simulations.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2001년도 학술대회논문집
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• pp.193-197
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• 2001

In this paper, reduction characteristics of the ac flashover voltage in the horizontal air gap of sphere-sphere and needle-needle electrode system were investigated when the combustion flame was present near the high-voltage electrodes. The reduction characteristics of ac flashover voltage were discussed with thermal ionization process, the relative air density and the deflection phenomena in the shape of flames that changed by the corona wind and coulomb's force. As the results of an experimental, It was found that the reduction of flashover voltage in sphere-sphere system, in comparison with the no-flame case, are 79.9 [%] for k=0, 82.9 [%] for k=0.5, 87.5 [%] for k=1.0, 85.0 [%] for h=0 [cm], 40.8 [%] for h=5 [cm] and 28.2 [%] for h=9 [cm] when ac voltage is applied.

• 한국연소학회지
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• 제11권4호
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• pp.1-8
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• 2006

The model cavity scramjet engine experiments are carried out using T3 free-piston shock tunnel. Upstream hydrogen fuel is injected before the cavity with different injection pressure. OH planar laser-induced fluorescence is used to investigate the combustion zone and piezoelectric pressure transducers are used to define the pressure rise due to the combustion. Main combustion region is a mixing layer which is between air and fuel. Also high OH fluorescence signal is appeared in the shear layer above the cavity in high equivalence ratio. From the OH signal in the cavity, this fuel injection system can be a role as a flame-holder.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제32회 KOSCO SYMPOSIUM 논문집
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• pp.197-204
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• 2006

The model cavity scramjet engine experiments are carried out using T3 free-piston shock tunnel. Upstream hydrogen fuel is injected before the cavity with different injection pressure. OH planar laser-induced fluorescence is used to investigate the combustion zone and piezoelectric pressure transducers are used to define the pressure rise due to the combustion. Main combustion region is a mixing layer which is between air and fuel. Also high OH fluorescence signal is appeared in the shear layer above the cavity in high equivalence ratio. From the OH signal in the cavity, this fuel injection system can be a role as a flame- holder.