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다양한 가스터빈을 사용하는 하이브리드 시스템의 SOFC/GT 설계 성능 및 민감도 해석
명노성(No Sung Myung),박성구(Sung Ku Park),손정락(Jeong Lak Sohn),김동섭(Tong Seop Kim) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
This study aims to analyze the influence of the gas turbine power size on the performance of the hybrid power system combining a solid oxide fuel cell (SOFC) and a gas turbine (GT). Three hybrid systems adopting different gas turbines (㎾, sub-㎿, multi-㎿ classes) are designed, and their performances are compared. The SOFC performance remains constant. Parametric analyses are performed considering variable design parameters such as pressure ratio, and results are compared among different design cases. Also, sensitivity analyses are performed to examine the influence of the component characteristic parameters such as component efficiency on the performance of the entire system.
가스터빈의 규모별 성능차이를 고려한 고체산화물 연료전지/가스터빈 하이브리드 시스템의 성능해석
명노성(No Sung Myung),박성구(Sung Ku Park),김동섭(Tong Seop Kim) 대한기계학회 2011 大韓機械學會論文集B Vol.35 No.4
고체산화물 연료전지(SOFC)와 가스터빈을 결합한 하이브리드 발전시스템에서 가스터빈의 규모별 성능차이가 시스템의 성능에 미치는 영향에 대하여 해석하였다. 이를 위해 ㎾급, ㎿ 이하급, 수 ㎿급 등 서로 다른 세 가지 가스터빈을 선정하여 사용하였다. 가스터빈이 순 출력을 거의 내지 못하는 ㎾급 시스템에서도 연료전지 단독 시스템과 비교해 효율이 증가하였으며, 가스터빈의 출력이 커질수록(즉, 성능이 좋아질수록) 하이브리드 시스템에서 가스터빈이 차지하는 비중이 커지고 시스템의 효율이 높아짐을 확인하였다. 가스터빈의 압력비 증가에 따른 성능 변화를 살펴본 결과 세 가지 하이브리드 시스템에서 모두 출력은 증가하지만, 효율의 변화는 크지 않음을 확인하였다. This study analyzes the performance of hybrid power systems combining a solid oxide fuel cell (SOFC) and a gas turbine (GT). Research focus is given to the influence of the size-dependent gas turbine performance on hybrid system performance. Three hybrid systems adopting different gas turbines (㎾, sub-㎿, multi-㎿ classes) are designed. As the gas turbine power increases (i.e. as the gas turbine performance enhances), the gas turbine power portion increases and the hybrid system efficiency increases. The hybrid system shows efficiency improvement over the SOFC only system even in the case where the gas turbine net power is nearly zero. The increase of gas turbine pressure ratio contributes to the net hybrid system power output in all of the three cases, while system efficiency is almost independent on the pressure ratio.
정준우,명노성 한국진공학회 2014 Applied Science and Convergence Technology Vol.23 No.6
Diffusion coefficient of Fe in polycrystalline host ZnSe as a mid-IR gain medium has beenmeasured in the annealing temperature ranges of 850 to 950oC. The synthesis of the sampleswas carried out in quartz ampoule in which the Fe thin film deposited by physical vaporevaporation method on the ZnSe. One can realize that the diffusion coefficient strongly dependson the surface active surfactants through the cleaning process and the substrate temperatureduring the thin film deposition leading to 2.04×10-9 cm2/s for Fe2+:ZnSe. The Annealingtemperature dependence of the Fe ions diffusion in ZnSe was used to evaluate the activationenergy, Ea=1.39 eV for diffusion and the pre-exponential factor D0 of 13.5 cm2/s.
Femtosecond Mid-IR Cr:ZnS Laser with Transmitting Graphene-ZnSe Saturable Absorber
조원배,배지은,이승철,명노성,이상민 한국광학회 2023 Current Optics and Photonics Vol.7 No.6
Graphene-based saturable absorbers (SAs) are widely used as laser mode-lockers at various laser oscillators. In particular, transmission-type graphene-SAs with ultrabroad spectral coverage are typically manufactured on transparent substrates with low nonlinearity to minimize the effects on the oscillators. Here, we developed two types of transmitting graphene SAs based on CaF 2 and ZnSe. Using the graphene-SA based on CaF 2 , a passively mode-locked mid-infrared Cr:ZnS laser delivers relatively long 540 fs pulses with a maximum output power of up to 760 mW. In the negative net cavity dispersion regime, the pulse width was not reduced further by inhomogeneous group delay dispersion (GDD) compensation. In the same laser cavity, we replaced only the graphene-SA based on CaF 2 with the SA based on ZnSe. Due to the additional self-phase modulation effect induced by the ZnSe substrate with high nonlinearity, the stably mode-locked Cr:ZnS laser produced Fourier transform-limited ~130 fs near 2,340 nm. In the stable single-pulse operation regime, average output powers up to 635 mW at 234 MHz repetition rates were achieved. To our knowledge, this is the first attempt to achieve shorter pulse widths from a polycrystalline Cr:ZnS laser by utilizing the graphene deposited on the substrate with high nonlinearity.
이정호(Jeong Ho Lee),명노성(No Sung Myung),김동섭(Tong Seop Kim) 대한기계학회 2011 大韓機械學會論文集B Vol.35 No.6
다양한 작동 조건에서 고분자 전해질형 연료전지의 성능 변화를 예측하기 위한 해석 프로그램을 구성하여 열관리가 시스템의 성능에 미치는 영향을 해석하였다. 전체 시스템은 연료전지 스택, 공기공급계, 연료공급계, 열 관리계로 구성 되었으며 각 구성부의 설계점을 고려하여 열역학적 모델링을 적용하였다. 외기온 변화와 냉각 시스템의 성능 변화에 따라 연료전지 스택의 온도 및 출력 변화가 예상되므로 탈설계 해석을 하여 전체 시스템의 성능 변화를 예측하였다. An analysis program to simulate the operation of a polymer electrolyte membrane fuel cell (PEMFC) system was set up, and system operation with variations in the working conditions of various components (especially the thermal management system) was simulated. The entire system included a PEMFC stack and balance-of-plant components such as an air-supply unit, a fuel-supply unit, and a heat-management unit (cooling system). Thermodynamic models of all components were made to evaluate the design performance of the entire system, and then off-design models were set up to simulate the operation of the entire system under arbitrary working conditions. A parametric study was carried out to examine the effects of varying the operating conditions (especially the ambient conditions and the operating conditions of the cooling system) on the operation and performance of the entire system.
이정호(Jeong Ho Lee),명노성(No Sung Myung),김동섭(Tong Seop Kim) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
An analysis program to simulate the operation of a PEMFC system was set up and system operation due to variations in working conditions of components, especially the heat management system, was simulated. The entire system includes a PEMFC stack and balance-of-plant component such as air supply unit, fuel supply unit and heat management unit, i.e. cooling system. Thermodynamic models of all components were made to evaluate the design performance of the entire system, and then off-design models were made to simulate operation of the entire system under arbitrary working condition. A parametric study was performed to examine the effect of varying operating conditions, especially the ambient condition and the operating condition of cooling system, on the operation and performance of the entire system
Kwangwook Park,Sooraj Ravindran,주건우,Jung-Wook Min,Seokjin Kang,명노성,Sang-Youp Yim,조용륜,김봉중,Yong-Tak Lee 한국물리학회 2016 Current Applied Physics Vol.16 No.12
GaAs/GaInAs multiple-quantum-well (MQW) shells having different GaInAs shell width formed on the surface of self-catalyzed GaAs core nanowires (NWs) are grown on (100) Si substrate using molecular beam epitaxy. The photoluminescence emission from GaAs/GaInAs MQW shells and the carrier lifetime could be varied by changing the width of GaInAs shell. Time-resolved photoluminescence measurements showed that the carrier lifetime had a fast and slow decay owing to the mixing of wurtzite and zincblende structures of the NWs. Furthermore, strain relaxation caused the carrier lifetime to decrease beyond a certain thickness of GaInAs quantum well shells.