• 생물환경조절학회지
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• 제1권2호
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• pp.169-174
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• 1992

간격침적식 수경재배의 실용화 가능성을 검사하고자 10분간격 간격침적식, 15분간격 간격침적식, NFT식 및 분무경system을 이용하여 토마토에 대한 생육비교 실험을 수행하였다. 1. 초장은 NFT식에서 가장 양호하였으나 주근장은 간헐침지식에서 길었으며 수경과 엽수는 처리간에 차이가 없었다. 2. 생체중과 건물중은 생육초기에는 NFT에서 무거웠으나 생육이 진전될수록 간헐침지식에서 더 무거워졌다. 3. 처리 후 43일의 개화수는 분무경 18.5, 15분간격 간헐침지식 17.8, 10분간격 간헐침지식 16.8, NFT 15.1개 순이었으며 과중은 분무경에서 149.1g으로 가장 무거웠다. 4. 식물체당 평균수량은 분무경에서 1929.1g으로 가장 많았고 10분간격 간헐침지식에서 1475.2g으로 다음이었으며, NFT식 및 15분간격 간헐침지식에서 각각 1276.2, 1084.8g으로 가장 적었다. 5. 식물체당 평균수호과수는 분무경 11.0, NFT식 9.7, 15분간격 간헐침지식 8.3, 10분간격 간헐침지식 7.7개 순이었으며 평균과중은 분무경 192.9, 10분간격 간헐침지식 172.4, NFT식 134.0, 15분간격 간헐침지식 126.0 순이었다. 6. 평균과장은 분무경과 10분간격 간헐침지식에서 NFT식과 15분간격 간헐침지식보다 길었으며 평균과폭은 NFT식, 분무경 및 10분간격 간헐침지식에서 비슷한 정도로 15분간격 간헐침지식보다 켰다.

• 한국분무공학회지
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• 제5권1호
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• pp.30-40
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• 2000

The characteristics of liquefied butane spray are expected to be different from conventional diesel fuel spray, because a kind of flash boiling spray is expected when the back pressure is below the saturated vapor pressure of the butane(0.23MPa at 298K). The ambient pressure was held at a pressure above(0.37MPa) and below(0.15MPa) the fuel vapor pressure. The axial velocities, radial velocities, and size distributions in butane sprays were measured with PDPA(Phase Doppler Particle Analyzer) system. The PDPA measurement showed a smaller SMD at the 0.15MPa chamber pressure, compared to the 0.37MPa case. Log-hyperbolic density function for the droplets size distribution can be fitted to the experimental results of a liquefied butane spray.

• 한국자동차공학회논문집
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• 제5권3호
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• pp.128-136
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• 1997

Spray characteristics of a fuel injector have an important effect upon engine power and emission. Thus this study was investigated the spray characteristics of the intermittent injection using a gasoline fuel injector. Image processing system and PDA system were utilized for visualization of a spray behavior and measurements of a droplet size and velocity, respectively. Fuel injection duration was fixed with 3ms and injection pressure was varied such as 250kPa, 300kPa, 350kPa. for a high fuel injection pressure, spray tip arrival time was fluctuated at a vigorously disintegrated cross section. Axial velocity was linear correlated with fuel droplet size in the time interval of an injected main spray at spray downstream.

• 한국분무공학회지
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• 제3권1호
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• pp.34-42
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• 1998

The correlation between the droplets size and the velocity are investigated for an intermittent spray of the pintle type fuel injector employed in a port injection gasoline engine. The analysis such as the mean droplet size, SMD, and velocity under the fixed injection period and varied fuel pressures are conducted utilizing PDPA systems. As results, the experimental data obtained, show that the larger droplet sizes. the higher velocities during the spray tip arrival time, and that at Z=70mm, r=8mm, both droplet sizes and velocities are peak. At the upstream, flow of droplets are dominated by injection pressure, which are more effected inertia force of droplets at the downstream of Z=70mm.

• 한국생물환경조절학회:학술대회논문집
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• 한국생물환경조절학회 1992년도 학술논문발표요지
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• pp.29-30
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• 1992

최근 근권의 산소부족 문제를 근본적으로 해결할 수 있는 수경능법으로서 분무경에 관한 관심은 매우 높으며 분무경의 우수성이 실증적으로 제시되고 있으나 분무경의 경우 고압을 필요로 하므로 장치가 복잡해지거나 엽체류의 경우 분무노즐과의 거리에 따라 생장이 균일하지 않는 문제점을 갖고 있으므로 분무경과 같이 근권산소 문제를 근본적으로 해결하는 효과를 가지면서도 취급 및 관리가 편리한 수경시스템의 개발이 절실히 요구되고 있다. (중략)

• 대한기계학회논문집B
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• 제21권9호
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• pp.1198-1206
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• 1997

The flow characteristics of an intermittent fuel injection into a stationary ambient air were investigated using gasoline. The measurements were made by two-channel, air cooling type Phase Doppler Anemometer(PDA) system (DANTEC, 750 MW). And a pintle type injector of MPI (Multi-point Port Injection) system was utilized as a fuel injector. The PDA receiver optic was set up in a 60.deg. C forward scatter arrangement to obtain the optimum scattering signal of fuel droplets. The data were obtained by synchronizing PDA system with the fuel injection period, and the axial and radial velocity and turbulent components of fuel droplets were mainly measured for the analysis of temporal and spatial distribution depending upon the fuel injection pressures.

• Journal of Advanced Marine Engineering and Technology
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• 제28권3호
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• pp.466-474
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• 2004

The characteristics of liquefied butane spray are expected to be different from conventional diesel fuel spray, because a flash boiling spray is expected when the surround pressure is below the saturated vapor pressure of the butane(0.23MPa 98K). The axial velocities. radial velocities. and size distributions in butane sprays were measured with PDPA(Phase Doppler Particle Analyzer) system. Sprays were macroscopically observed by using the high speed camera in case that the surround pressure is 0.37MPa and 0.15MPa. respectively. Compared with the conventional spray. the reversed results were investigated when the surround pressure is below the saturated vapor pressure of the butane.

• 한국분무공학회지
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• 제4권1호
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• pp.45-54
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• 1999

The spray characteristics of a direct injection multi-hole diesel nozzle having the 2-spring nozzle holder were investigated by using the image processing system and a PDPA(phase Bowler particle analyzer) system. The spray tip penetration, the spray angle, and the droplet diameter and velocity with the variation of the pump speed, injection quantity were measured. From, the experiments, we know that there are small droplets which are not to be detected with spray image around the leading edge of the spray. In order to represent the mean characteristics of the intermittent spray very well, it is very important to set the time windows accurately. From the measurements along the axis of the spray, close to the nozzle, the initially injected droplets are overtaken by droplets that follow them. And also there are the maximum axial mean velocity and SMD at the following part of the leading edge of the spray.

• 한국자동차공학회논문집
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• 제9권3호
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• pp.27-34
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• 2001

This experimental study is to investigate the intermittent spray characteristics of the multi-hole diesel nozzle with a 2-spring nozzle holder. Without changing the total orifice exit area, its hole number varied from 3($d_n=0.42mm$) to 8($d_n$=0.25mm). Through the use of the 2-D PDPA(phase Doppler particle analyzer), the droplet diameter and the velocity of the diesel spray injected intermittently from the multi-hole nozzle into the still ambient were measured. And the calculations of time-resolved diameters, SMD and AMD were made. The results can be summarized as follows. The spray of the multi-hole nozzle consisted of three parts. These are the leading edge, the central part and the trailing edge. And most of droplets produced at the trailing edge of spray. In the spray flow field, the measuring position which represented the intermittent spray characteristics well was near the nozzle tip. But at the downstream of the spray, its characteristics disappeared, and spray behavior showed a quasi steady state regardless of the time evolution of the spray. The overall mean SMD of the spray increased with the spray development, and showed their maximum value near 1.5ms regardless of hole number.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.801-806
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• 2000

This experimental study is to investigate the intermittent spray characteristics of a multi-hole nozzle in a heavy-duty DI diesel engine. Multi 8 hole$(d_n=0.25mm)$, Multi 3 hole$(d_n=0.42)$ and Sing hole nozzle$(d_n=0.25mm)$ were used in this experiment. By using the 2-D PDPA(phase Doppler particle analyzer), the droplet diameter and the velocity of a diesel spray injected intermittently from the multi and the single-hole nozzle into a still ambient were measured. In order to calculate the mean values such as mean velocity, SMD, AMD etc. and to analyze the intermittent characteristics, the time-window of 0.15ms were applied. In the spray, the small droplet$(D<10{\mu}m)$ was regarded as an air flow, and the correlation between the fuel droplet$(10{\mu}m and the air (low was examined. The normalized axial droplet-air relative velocity of the 8 hole, the 3 hole and the single hole nozzle was evaluated as 0.081, 0.067, 0.06 and in case of the radial droplet-air relative velocity, the normalized. value is 0.014, 0.013 and 0.008 respectively.