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밀폐용기내의 물의 저압 증발 최적조건에 관한 실험적 연구
김세현(S. H. Kim),신유식(Y. S. Shin),이윤환(Y. W. Lee),정효민(H. M. Jeong),정한식(H. S. Chung) 한국동력기계공학회 2004 동력시스템공학회지 Vol.8 No.1
Cooling towers are widely used not only for cooling products and equipment in manufacturing process but HVAC(Heating, Ventilation and Air Conditioning) system. As a cooling tower is the terminal apparatus which discharges heat from industrial process, the efficiency of heat exchange in the cooling tower greatly affect to the overall performance of a thermal system. In this paper, we constituted a new water cooling system by using a Latent heat of evaporation in an enclosed tank, and this system is consisted of an enclosed vacuum tank and water driven ejector system. Several experimental cases were carried out for improvement methods of high vacuum pressure and water cooling characteristics. The ejector performance was tested in case of water temperature variations that flows into the ejector. Based on the vacuum pressure by water driven ejector, the water cooling characteristics were investigated for the vaporized air condensing effects.
하류 유동제어에 의한 에젝터의 효율상승 방법에 관한 연구
김세현(S. H. Kim),이상철(S. C. Lee),신유식(Y. S. Shin),최석천(S. C. Choi),정효민(H. M. Jeong),정한식(H. S. Chung) 한국동력기계공학회 2004 한국동력기계공학회 학술대회 논문집 Vol.- No.-
The ejector system is used for making a low pressure in industrial field. The ejector is consists of nozzle, mixing section and diffuser. The diffuser is influenced in low pressure of ejector system. The diffuser is an important fluid-mechanical equipment to convert kinetic energy into pressure energy. Many of the experimental and theoretical researches have been done in a diffuser but the understanding of energy transfer and detailed mechanism of energy dissipation is unclear. In this study, computations were performed using a numerical method with SIMPLE algorithm for conical diffuser with various diffuser angles and Reynolds number. Also, we investigated the pressure recovery coefficient in conical diffuser by inserting strut. In this paper, we showed that the strut can cause a rising pressure recovery.
이상철(S. C. Lee),김영근(Y. G. Kim),이효덕(H. D. Lee),김세현(S. H. Kim),정한식(H. S. Chung),정효민(H. M. Jeong) 한국동력기계공학회 2004 한국동력기계공학회 학술대회 논문집 Vol.- No.-
The latent heat of evaporation of LNG is very effective and this generated in vaporization process of LNG. This energy is evaluated with value of 199.12 ㎉/㎏ (1.03 atm, -16 1 ~ 0℃). The purpose of this study represents the heat exchange characteristics of super low temperature liquefied natural gas. As the experimental liquefied gas, LN₂ was used in experiment and the main experimental parameter is chosen the flow rate and inflow air velocity. The experiment was performed for twenty minutes with several times. Temperatures distributions were obtained by T-type thermocouples. The heat exchange effects were dropped by a moisture freezing at heat exchange surface and various inlet air velocity were considered for temperature environment in chamber.
최석천(S. C. Choi),이해종(H. J. Lee),김세현(S. H. Kim),고대권(D. K. Koh),정효민(H. M. Jeong),정한식(H. S. Chung) 한국동력기계공학회 2004 동력시스템공학회지 Vol.8 No.1
In this study, a computer analysis has been developed for predicting the pipe pressure of the intake and exhaust manifold. To obtain the boundary conditions for a numerical analysis, one dimensional and non-steady gas dynamic calculation is performed by using the MOC(Method Of Characteristic). The main numerical parameters are the variation of the engine revolution to calculate the pulsating flow which the intake and exhaust valves are working. The comparison of exhaust pressure in case of numerical results is quite matched with in case of experimental results. When engine revaluation is increased, the pressure amplitude showed a high value, but the pressure frequency was decreased.
정효민(H.M. Jeong),최석천(S.C. Choi),심규진(K.J. Sim),김세현(S.H. Kim),고대권(D.K. Koh),정한식(H.S. Chung) 한국동력기계공학회 2004 동력시스템공학회지 Vol.8 No.4
본 연구는 단기통 4행정 기관의 배기단의 형상에 따른 실험과 수치해석이 소개되었다 흡ㆍ배기 밸브가 작동하고 있고, 주요한 배기단의 변수로는 배기단 직경이 적용이 되었다. 실험결과로는 배기 단의 직경에 따라 배기 압력은 많은 영향을 받았는 것으로 나타났다. 배기단의 직경이 감소하였을 때, 배기압력파의 진폭과 파수가 증가되었다. 배기단의 직경이 증가 하였을 때, 배기압력파의 진폭이 감소하였다. 직경이 22㎜ 일 때의 소음의 주파수 분석이 16㎜와 28㎜ 보다 진폭이 작게 나타났다.
백승도(S.D. Baek),김종화(J.H. Kim),김세현(S.H. Kim),최상주(S.J. Choi) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.7
KEPCO is executing a project in Cambodia consisting of two components, "Power Development Master Plan and Institutional Strengthening" and "Greater Mekong Sub-region (GMS) Power Project Preparation" upon request by the government of the Ministry of Industry, Mines and Energy of Cambodia, contracted on 29<SUP>th</SUP> September 2005. This paper includes a basic design and review of economical efficiency for constructing the two (2) cross border 115 ㎸ transmission lines, which run from the border of Vietnam and Laos to Cambodia, and four (4) 115 ㎸ substations The main contents of the paper include the process of design and results of a review of line route selection, tower and hardware design regarding transmission line design, as well as the type of substation, and arrangement and specifications of equipment with expects to substation design. Also, long-term demand forecasting, and an economic analysis of the project area are included.
PIV를 이용한 육상 수조식 양식장의 유동특성에 관한 연구
김보한(B. H. Kim),김세현(S. H. Kim),이중섭(C. S. Yi),심규진(K. J. Shim),이철재(C. J. Lee),정효민(H. M. Jeong),정한식(H. S. Chung) 한국동력기계공학회 2004 한국동력기계공학회 학술대회 논문집 Vol.- No.-
The aquaculture tank is used for a breeding fish by using sea water. This aquaculture system is free from the marine pollutions and outside sea water conditions. But a land aquaculture tank needs more wide space and the equipment of circulating sea water system. The design of land aquaculture tank is very important to the growth of fish. Therefore, the water circulating system affects to the water temperature and velocity of flow in a land aquaculture tank. There are many kinds of the aquarium tank, the general type have circle shape and rectangular shape which is rounded four corner. But the optimum design of aquarium researches seems to be lacking at the view of engineering. In this study, we adopted the rectangular shape with round off a corner type. The PIV was adopted to study the basic flow characteristics of experimental model. This paper is intended as an investigation of the flow characteristics in aquarium tank, and we could obtained on the flow pattern and velocity distributions.