• 한국화재소방학회논문지
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• 제28권6호
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• pp.47-51
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• 2014

본 연구에서는 태양광 발전설비가 설치되어 있는 건물에서 화재가 발생할 경우 분사되는 물을 통해 전류가 흐를 가능성 및 감전의 위험성에 대해 고찰하였다. 분사되는 물을 수학적 모델을 통하여 해석 하였고, 물 전도도 측정을 위한 물분사 시스템을 제작하여 유속에 따른 물 저항값을 측정하여 수치적으로 예상한 값과 비교하였다. 실험과 수치계산의 결과로 태양광 발전설비 화재 시 고려되어야 할 사항들을 정의할 수 있게 되었다.

• 한국화재소방학회논문지
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• 제27권3호
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• pp.38-46
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• 2013

산불로부터 주요 산림과 시설물들을 보호하고 주변 확산을 저지하기 위해서는 상설 급수 및 살수시설이 반드시 필요하다. 우리나라에서는 2005년 양양산불로 인해 낙산사 소실을 경험하면서 주요문화재 건축물 주변에 숲 관리와 함께 산불방지 급수시설 설치사업을 단계적으로 실시하였다. 하지만 기존 설치된 산불방지급수시설의 경우, 별도의 설치와 관리를 위한 기준을 마련하지 않고 각 시공업체의 시방서를 기준으로 설치하였다. 시공업체의 시방서는 NFSC 109를 토대로 산림지역에 변형하여 설치한 것으로 광범위한 산불확산으로부터 주요시설물 등을 효과적으로 보호하기에는 방호면적이 적고 호스의 이동과 동시살수에 있어 제한적인 단점들을 가지고 있다. 이에 본 연구에서는 국내에서 설치되어 이용하고 있는 산불방지 급수전의 실태조사를 실시하여 문제점들을 도출하였고 이를 보완할 수 있는 성능위주의 산불방지 급수시설 기준을 마련하였다. 그 결과, 산불방지 효과를 높이기 위한 방법으로 산불방지 급수시설의 구성을 수관화 확산방지를 위한 'Water Sprinkler Tower System', 지표화 진화를 위한 'Forest Fire Hydrant System', 'Portable Water Spray System' 3가지를 제시하였고 설치를 위한 펌프의 성능 및 부속품들에 대한 기준을 제시하였다.

• 설비공학논문집
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• 제28권7호
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• pp.269-274
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• 2016

This paper aims to suggest the water curtain installation guideline for prevention of fire spread. The water curtain systems play a role in preventing fire spread which is caused by fire flames and radiation heat release from a fire source. The radiation attenuation ratio is affected by the water droplet size, vertical distance from the nozzle and flow rate. This study suggests the water curtain installation guideline as follows : (1) Investigation of a reference store array (2) Calculation of the number of drencher heads (3) Review of the relationship between droplet size and attenuation factor depending on the height of the drencher head (4) Review of a drencher head array and spray overlapping. The reference traditional market in which a fire compartment is installed using a water curtain can be predicted to have a radiation attenuation ratio of 50%.

• 한국분무공학회지
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• 제23권2호
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• pp.96-101
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• 2018

The purpose of this study is to investigate the effect of water injection on combustion characteristics of gasoline direct injection (GDI) engine with turbo-charger under low-load operating condition. The test engine used in this study has four-cylinder and 10.2 of compression ratio. In order to study the effect of water injection ratio on combustion characteristics, the water was injected into the intake port from 10% to 50%, based on fuel injection quantity. From the experiment, it revealed that the water injection induced the improvement of fuel economy because of the advance of spark-timing by the reduction of in-cylinder temperature. In addition, the water injection caused the prolong of extension of the ignition delay and slight increase of burn duration.

• 한국분무공학회지
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• 제28권1호
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• pp.10-15
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• 2023

Recently, various types of towels and dishcloth dryer products are being widely distributed in Korea. Evaluation methods for water absorption properties of various fabrics have been developed, and there are many studies using them. This study newly intended that whether it is possible to obtain data that can quantitatively analyze the water absorption characteristics of various fabrics, to show the correlation between the water absorption height and the amount of water (water holdup) absorbed, and to experimentally suggest the applicability to evaluate the drying capacity of towel dryer using IR camera. Through these experiments, it was confirmed that quantitative data on the water absorption height of various fabrics can be measured using an IR camera and can be clearly applied to the performance evaluation of actual products.

• Journal of Biosystems Engineering
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• 제41권3호
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• pp.201-207
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• 2016

Purpose: A water-spraying type automatic glochids removal system for cactus (Opuntia humifusa) stem was developed, and its performance was evaluated. The system was developed to reduce intensive human labor in removing glochids from cactus stem skin without inducing damage prior to further processing into value-added products. Methods: The developed system consists of conveyor and water-spraying systems. The conveyor system delivers cactus stems through water-spraying compartments and finally to a collecting box. In order to remove the glochids, rotating nozzles spray water over all areas (i.e., front and back faces and sides) of the cactus skin under controlled water pressure. Operating conditions such as conveyor speed, water pressure, angle of water-spraying nozzles, distance between conveyor belt and rotating nozzles, and angle of cactus flipping slide were adopted from our previous study and applied on the system design and manufacturing. The performance of glochids removal was evaluated by counting the number of glochids on the cactus stem before and after processing on the system. Results: The developed system performed efficiently and effectively under the pre-studied operating conditions except for the angle of cactus flipping slide. The new system had a glochids removal ratio of 94.1% without damaging the cactus skin. Considering the original number (approximately 30-60) of glochids, the remaining number was low (1-4), and most of them were found at the side edge of the cactus stem. This system can remove glochids from 360 cactus stems in 1 hr regardless of cactus size. Conclusions: The performance of the new system in glochids removal without damaging cactus skin is superior to any other existing device (i.e., brush type, rubber-friction type, and agitation type). The system is expected to be applied in cactus (O. humifusa) processing facilities.

• 한국분무공학회지
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• 제13권3호
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• pp.156-161
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• 2008

The present article reports a numerical study on the fire characteristic change by water-mist in under-ventilated compartments. The natural gas and heptane pool fires are used as fire sources, which are located in the bottom center of the 2/5 reduced-scaled model of the ISO 9705 standard room. The fire modeling using the FDS (Fire Dynamics Simulator) is validated by comparison with previously published experimental results. For temperature and combustion gas concentrations at two positions located in the upper layer of compartment, the predicted results with and without water-mist are compared each other. The results show that under the water-mist operation, the predicted temperature and carbon monoxide concentration reduce as $300{\sim}400^{\circ}C$ and about 20%, respectively, compared to those without water-mist.

• Composites Research
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• 제23권1호
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• pp.44-50
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• 2010

본 연구에서는 염수 침수 실험과 염수 분무 실험이라는 두 가지의 실험을 위그선의 구조재료로 사용될 3가지 다른 복합재료 시스템에 대해서 해수와의 접촉에 의한 물성저하를재현하기 위해 수행하였다. 140일간 염수환경하에서 노화시킨 후 탄소섬유 복합재료와유리섬유 복합재료의 인장, 압축, 전단 강성과 강도 및 층간 전단 강도를 측정하였다. 기본 물성파의 비교를 통해서 염수환경이 복합재료의 기계적 물성에 미치는 영향이 평가되었다. 실험을 통해 염수 분무환경과 침수 환경의 차이는 거의 영향을 미치지 않음을 확인하였다. 탄소섬유 복합재료의 경우 인장 물성에 적은 손실이 발생한 반면 유리섬유 복합재료에서는 인장물성의 저하률이 탄소섬유 복합재료에 비해서 큼을 확인하였다. 그리고 모재 지배적 물성들의 큰 물성저하가 관찰되었다. 이를 통해, 염수는 복합재료의 섬유와 모재 사이의 계면을 퇴화시키고, 또한 모재 자체 물성과 유리섬유의 물성을 저하시킬 수 있음을 확인하였다.

• 한국분무공학회지
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• 제2권1호
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• pp.29-35
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• 1997

Many technologies have been developed to improve diesel emissions or performance, however NOx/PM trade-off occurs because normal methods that reduce NOx emissions tend to increase PM emissions. On the other hand many measures used to control PM emissions tend to increase NOx emissions. Thus, simultaneously controlling both NOx and PM emissions has become a significant challenge for diesel engine manufacturers. As one of the measures, the technology using emulsified fuel has recently become important under the stringent emission regulations of diesel engines. This paper investigates injection characteristics of emulsified fuel and its effect on a combustion performance in a diesel engine. In order to supply emulsified fuel into injection system a mixing unit produced by Harrier is used, then the fuel mixed with water is supplied into injector directly. The spray injected is investigated with a shadowgraph photo system and injection analyzing apparatus, then applied into a diesel engine. Those results showed that the emulsified fuel has an effect on reducing both NOx and PM.

• 한국분무공학회지
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• 제11권2호
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• pp.75-80
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• 2006

The present article proposes a new droplet collision model including the stretching separation regime and the formation of satellite droplets. The new model consists of several equations to calculate the post-collision characteristics of colliding droplets and satellite droplets. These equations are derived from the energy balance of droplets between before and after collision. For binary collision of water droplets, the new model shows good agreement with experimental data far the number of satellite droplets.