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2차 모멘트 난류모형에 의한 회전하는 평행 평판유동 해석
신종근,최영돈,Shin, Jong-Keun,Choi, Young-Don 대한기계학회 2000 大韓機械學會論文集B Vol.24 No.4
A low-Reynolds-number second moment turbulence closure is improved with the aid of DNS data. For the model coefficients of pressure-strain terms, we adopted Shima's model with some modification. Shin and Choi's new dissipation-rate equation is employed to simulate accurately the turbulence energy dissipation rate distribution in the near wall sublayer. The results of computations are compared with DNS, LES data and experimental data for turbulent plane channel flow with rotation about spanwise axis. The present second moment closure achieves a level of agreement similar to that for the non-rotating. In particular, it accurately captures the distribution of turbulence energy dissipation rate in the near wall region.
고분자 전해질 연료전지 분리판 입구에 존재하는 직선유로의 깊이와 폭 변화에 따른 전산 해석
최영돈(Choi Young-Don),윤성호(Yun SungHo),신종근(Shin Jong-Keun),박명호(Park Myung-ho) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.5
PEMFC is popular energy system that is pollution free, high efficiency, sustainable in renewable energy. In this paper, analyses PEMFC straight separator’s performance on design variation at inlet part. Studies variation of voltage and pressure on depth and width at fixed channel and rib’s total width = 2㎜. When RAR = 1.5, AR= 1.0, be Resulted ideal case that supplies low pressure and middle power from this numerical analysis
최영돈(Choi Young-Don),남기훈(Nam Kihoon),신종근(Shin Jong-Keun),박명호(Park Myung-ho) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.5
PEMFC (polymer electrolyte membrane fuel cell) is device that generates electricity from hydrogen. It is one of the subjects related to renewable energy and various research has been conducted on the PEMFC. But the efficiency is very low compared to other fossil fuels, and further research is required to replace fossil fuels with PEMFC. Analysis of flow field pattern in supplying hydrogen and oxygen is part of the research to increase PEMFC efficiency. In this study, separation plate currently used in PEMFC is transformed to wave shape and mass transfer characteristics in the channel is examined through numerical analysis. Wave shape separation plate is expected to increase of efficiency compared to separation plate used in normal channel.
숙박업소 건물의 히트펌프 냉난방 시스템 적용을 위한 시뮬레이션 연구
최영돈(Young Don Choi),한성호(Seong Ho Han),조성환(Sung Hwan Cho),김두성(Du Sung Kim),엄철준(Chul Jun Um) 대한설비공학회 2008 설비공학 논문집 Vol.20 No.1
In Korea, air source heat pump system is less efficient than conventional heat source facilities, such as ground source, river water, because the air temperature in winter season is so low that COP of air source heat pump system drops below 3.0. Therefore, the study on the application of heat pump heating and cooling systems is crucial for the efficient popularization of heat pump. In this work, we present the dynamic analysis of energy consumption for the large resident building by heat resistance-capacitance method. The system simulation of water storage air source heat pump is additionally performed by changing of sizes and locations of the hospital building. The computed results show that energy cost of water storage air source heat pump is low, so it is mote economical than absorption chiller & heater.
공기극 채널 내 웨이브 형상의 돌기를 갖는 고분자 전해질 연료전지의 실험적 연구
최영돈(Choi Young-Don),최남현(Choi Nam-hyeon),신종근(Shin Jong-Keun),박명호(Park Myung-ho) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.5
In this study, we propose a wave-like design on surface of the cathode channels(Wave-form cathode channels) to improve oxidant delivery to the gas diffusion layers (GDLs). Experiments have been performed using PEMFCs combined with the wave-like surface design on cathodes. The cathode gas delivery channels were made of graphite. The variation factors are distance between wave-bumps (Adhesive Distance, AD) and size of the wave-bumps (Expansion Ratio, ER). AD are half-circle bump’s radius of 3, 4, 5 time size. And ER is channel’s height of 1/1.5, 1/2, 1/3 times. The performance of the fuel cells was evaluated and compared in the current-voltage (I-V) relation. For comparison, PEMFCs with conventional flat-surfaced oxygen channels have been prepared. The aim of this work is to identify the relationship between geometry of channels and fuel cell operation, and ultimate1y to find the optimal design of the cathode channels, maximizing fuel cell performance.
숙박업소 건물의 히트펌프 냉난방 시스템 적용을 위한 시뮬레이션 연구
최영돈(Young Don Choi),한성호(Seong Ho Han),조성환(Sung Hwan Cho),김주성(Ju Sung Kim),엄철준(Chul Jun Um) 대한설비공학회 2006 대한설비공학회 학술발표대회논문집 Vol.2006 No.6
Recently available heat pump system by using air heat-source is not efficient. Because the mean temperature of korean winter season is low, economy of air heat-source heat pump descend, and COP is below 3.0. This paper was practiced the simulation on evaluation criteria for heat pump heating and cooling systems to resident building. As a result, heating and cooling composition heat pump system apply to the building needed to be provided heat source for 24 hours.