• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2839-2844
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• 2007

Micro hydraulic power generation of which the output is less or equal to a 100kW is attracting considerable attention. This is because of its small, simple, renewable, and abundant energy resources. By using a small hydropower generator of which main concept is based on using the different water pressure levels in pipe lines, energy which was initially wasted by use of a reducing valve at the end of the pipeline, is collected by turbine in the hydropower generator. A propeller shaped hydroturbine has been used in order to use this renewable pressure energy. In this study, in order to acquire basic design data of tubular type hydraulic turbine, output power, head, efficiency characteristics due to the flow coefficient are examined in detail. Moreover influences of pressure and velocity distributions with the variations of runner vane angle on turbine performance are investigated by using a commercial CFD code.

• Journal of Advanced Marine Engineering and Technology
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• 제39권2호
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• pp.136-142
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• 2015

The shell and tube heat exchanger is an essential part of a power plant for recovering transfer heat between the feed water of a boiler and the wasted heat. The baffles are also an important element inside the heat exchanger. Internal materials influence the flow pattern in the bed. The influence of baffles in the velocity profiles was observed using a three-dimensional PIV (Particle Image Velocimetry) around baffles in a horizontal circular tube. The velocity of the particles was measured before the baffle and between them in the test tube. Results show that the velocity vectors near the front baffle flow along the vertical wall, and then concentrate on the upper opening of the front baffle. The velocity profiles circulate in the front and rear baffle. These profiles are related to the Reynolds number (Re) or the flow intensity. Velocity profiles at lower Re number showed complicated mixing to obtain the velocities and concentrate on the lower opening of the rear baffle as front wall. Numerical simulations were performed to investigate the effects of the baffle and obtain the velocity profiles between the two baffles. In this study, a commercial CFD package, Fluent 6.3.21 with the turbulent flow modeling, k-${\epsilon}$ are adopted. The path line and local axial velocities are calculated between two baffles using this program.

• Journal of Advanced Marine Engineering and Technology
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• 제32권7호
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• pp.1044-1050
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• 2008

Most of developed countries, the consumption of fossil fuels has been serious problems that cause serious environment pollution like acid rain, global warming. Also, we have faced that limitation fossil fuels will be exhausted. Currently, small hydropower attracts attention because of its small, clean, renewable, and abundant energy resources to develop. By using a small hydropower generator of which main concept is based on using the different water pressure levels in pipe lines, energy which was initially wasted by use of a reducing valve at the end of the pipeline, is collected by turbine in the hydropower generator. A propeller shaped hydroturbine has been used in order to use this renewable pressure energy. In this study, in order to acquire basic design data of tubular type hydraulic turbine, output power, head, efficiency characteristics due to the flow coefficient are examined in detail. Tubular-turbine among small hydraulic power generation can be used at low-head. The purpose of this study is to research turbine's efficiency due to runner vane angle using CFD analysis.

• 한국가스학회지
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• 제15권3호
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• pp.1-5
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• 2011

수소액화 공정은 수소 예냉 에너지, 액화에너지 그리고 Ortho/Para 변환열 제거 등 다량의 에너지가 요구되어 진다. 본 논문은 기존의 수소액화 공정에 LNG냉열을 이용하여 에너지절약 효과를 얻고자 기본설계 및 열해석을 수행하였다. 액화 소요에너지에 LNG냉열을 적용하면 수소액화공정의 에너지절약효과와 함께, LNG기지의 해수에 버려지는 LNG냉열을 회수, 이용하는 일석이조의 에너지절약기술이 된다. 열해석에 의한 설계를 수행한 결과 현재의 액체질소 예냉식 수소액화 플랜트의 소요에너지에 비하여 LNG냉열을 이용할 경우 소요동력량은 75%가 절감되었다. 이는 예냉을 액체질소 대신에 냉열을 사용하기 때문이다. 또한 LNG냉열량은 수소액화량 1T/D기준할 때 15T/D 유량이 요구되었다.

• 펄프종이기술
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• 제42권2호
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• pp.95-101
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• 2010

For the development of higher-sizing performance of paper, a sizing agent using recycled PET was synthesised. Polyester resin was extracted from wasted PET by subcritical hydrolysis and finally modified to synthetic sizing agent by mixing water-disperse PET with triphenyl phosphite(TPP). The modified PET was considered as an internal sizing agent in different wet-end papermaking conditions. The optimum condition in sizing efficiency was obtained in initial pH of 6.5 in case of rosin+alum system, and 7.5 in case of rosin+alum+PET system, respectively, and in addition amount of PET 3%. The sizing efficiency was also closely related according to the fiber properties of wet-end slurry, such as virgin fibres from UKP and recycled fibres from KOCC. The application of modified PET was good in strength improvement of paper, specially in tensile strength.

• Journal of Advanced Marine Engineering and Technology
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• 제32권6호
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• pp.908-914
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• 2008

The world is facing a serious energy problem which destroying the environment. In addition, fossil fuel such as oil and coal that caused global warming and the environmental problems due to acid rain had been gradually exhausted. To solve this problem that has crisis of energy, it is necessary time and effort for research and development of renewable energy in the future. As alternative energy, small hydropower generation which has output of less or equal to 100kW is attracting considerable attention. This is because of its small, simple, renewable, and large amount of energy resources. By using a small hydropower generator of which main concept is based on using the different water pressure levels in pipe lines, energy which was initially wasted by use reducing of a valve at the end of the pipeline, is collected by turbine in the small hydropower generator. In this study, we investigated the influence of the number of runner vanes on the characteristics of tubular-type hydroturbine.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2006년도 춘계학술논문 발표대회 제6권1호
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• pp.115-118
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• 2006

Nowadays the using of concrete is generalized, and construction material is demanded to be lightweight according to increasing the height and capacity of buildings. Therefore, it needs to develop the products having the great quality and various performance. Extruding concrete panel made of cement, silica source, and fiber, and it is a good lightweight concrete material in durability and thermostable. The silica of important ingredient is natural material with hish SiO2 contents and difficult in supply because of conservation of environment. On the other hand, the stone powder sludge discharged about 20-30% at making process of crushed fine aggregate and it is wasted. The stone powder sludge is valuable instead of silica ole because the stone powder sludge includes water of about 20-60%, SiO2 of about 64% and it has fine particles. This experiment is on the properties of extruding concrete panel using the stone powder sludge use instead of silica. From this experiment, we find that it is possible to replace the silica as stone power sludge up to 50%,

• Journal of Biosystems Engineering
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• 제29권1호
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• pp.21-28
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• 2004

Spraying is one of the most efficient methods for pesticide and insecticide control. Generally, orchard sprayers(aircarrier sprayer) are used for such applications. However, when an orchard sprayer is used, only 20% of total amount of spray deposits on the target. The rest of spray are not only wasted but are also potential sources of environmental pollution. The research far the development of electrostatic spraying system for orchard sprayer was conducted to develop the new pesticide application technology for the reduction of environmental pollution and f3r the production of safe agricultural products. The spray characteristics for nozzles with the different charging methods were tested and the effect of electrostatic charge was analyzed, in the laboratory experiments. The results of this study indicate that the capacitive type of electrostatic spraying nozzle exhibits a large current deposition of water sprays on the sample target. The covering area ratio by conventional spraying system was 10.2%, while that of electrostatic sprays with pulse induction charging method gave the increased covering area ratio by 4.3 times.

• 자원리싸이클링
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• 제3권1호
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• pp.44-51
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• 1994

PETqudds 부위별로 PET, HDPE, PVC, PP와 같은 여러 가지 다른 종류의 플라스틱으로 이루어져 있어 페 PET병의 재활용을 위하여서는 구성 성분별로 분리가 선행되어야 한다. 본 연구에서는 부상침강법에 의한 분리실험을 실시하였다. 수돗물을 사용하여 라벨을 제거한 후 부상침강 분리시키면 94%의 PET 회수율을 얻을 수 있었다. 라벨이 있을 경우에는 PVC와 PET가 침강하고 PP와 HDPE가 부상하므로 완전히 PET를 회수 할 수 없었다. 따라서 라벨을 제거시킨 후 분리를 시키든지 PVC 라벨의 재질을 PP나 PE로 교체하는 방안이 강구되어야 할 것으로 사료된다. 회수한 PET와 HDPE의 각종 물성을 측정하여 원재료와 비교해 본 결과 이들의 재활용이 가능함을 알 수 있었다.

• 자원리싸이클링
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• 제9권6호
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• pp.9-14
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• 2000

CSAC와 WPAC의 흡착특성을 보면 H공장 2차 처리수와 D공장 배출수에 함유된 ABS흡착에서 얻어진 Freundlich흡착등온식은 WPAC인 경우 q=23.12 $C^{ 0.42}$, q=18.32 $C^{0.38}$ 이고 CSAC인 경우 각각 $q=36.76C^{1.37}$ , q=26.67 $C^{0.42}$ 이었다. H공장 방류수의 파과점은 CSAC인 경우 680분이었고 WPAC는 610분이었다. 한편 D공장 배출수의 파과점은 CSAC인 경우 720분이었고 WPAC은 640분이었다. 이상의 결과로부터 CSAC 대체물로서 WPAC이 가능성이 있을 것으로 생각된다.