• 대한기계학회논문집B
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• 제35권9호
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• pp.923-932
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• 2011

본 연구에서는 복합화력발전소 가스터빈 출구가스 안내덕트 내부의 가스유동장이 배열회수보일러 전열기구에 미치는 영향을 CFD기법을 이용하여 분석하였다. 안내덕트 내부 난류흐름의 경우, 유속의 편차가 크고 선회 효과 및 상승류 현상이 심한 특징을 가지고 있음으로 이와 같은 유동의 수치해석을 위해 2개 방정식 난류점성 모델 중 RNG k-${\epsilon}$ 모델을 사용하였으며 유동장의 영향을 가장 많이 받는 배열 회수보일러 최종과열기관의 열전달특성변화를 파악하기 위하여 NTU 방식을 이용한 수치해석결과와, 산업계에서 적용하는 설계기법에 의한 결과를 비교하였다.

• 한국지진공학회논문집
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• 제19권1호
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• pp.37-43
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• 2015

This paper presents a detailed procedure for a nonlinear soil-structure interaction of a seismically isolated NPP(Nuclear Power Plant) structure using the boundary reaction method (BRM). The BRM offers a two-step method as follows: (1) the calculation of boundary reaction forces in the frequency domain on an interface of linear and nonlinear regions, (2) solving the wave radiation problem subjected to the boundary reaction forces in the time domain. For the purpose of calculating the boundary reaction forces at the base of the isolator, the KIESSI-3D program is employed in this study to solve soil-foundation interaction problem subjected to vertically incident seismic waves. Wave radiation analysis is also employed, in which the nonlinear structure and the linear soil region are modeled by finite elements and energy absorbing elements on the outer model boundary using a general purpose nonlinear FE program. In this study, the MIDAS/Civil program is employed for modeling the wave radiation problem. In order to absorb the outgoing elastic waves to the unbounded soil region, spring and viscous-damper elements are used at the outer FE boundary. The BRM technique utilizing KIESSI-3D and MIDAS/Civil programs is verified using a linear soil-structure analysis problem. Finally the method is applied to nonlinear seismic analysis of a base-isolated NPP structure. The results show that BRM can effectively be applied to nonlinear soil-structure interaction problems.

• 한국지진공학회논문집
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• 제12권5호
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• pp.57-63
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• 2008

본 연구는 원자력발전소에 설치되는 캐비닛형 전기기기의 동적 진동시험 자료를 이용하여 캐비닛의 지진응답을 예측할 수 있는 기법을 제안하였다. 제안된 기법은 1) 절점질량 이상화 모델에 기반한 등가 지진하중 산정, 2) 진동시험자료에 기반한 캐비닛 구조의 입출력 상태방정식 규명, 3) 산정된 등가지진하중과 규명된 입출력 상태방정식을 사용한 지진응답산정의 과정으로 구성된다. 제안된 기법은 유한요소기법(FEM) 모델 개선(Model Updating)에 기반한 지진응답예측기법에 비하여 모델링 오차가 개입 되지 않는 장점을 가진다. 캐비넷 구조를 이상화한 2차원 프레임 모델과 3차원 상세 모델에 대한 수치검증을 통하여 제안된 기법이 지진응답을 매우 정확하게 예측을 함을 관찰하였고, 측정 노이즈에 대해서도 강인함을 관찰하였다. 추후연구로 실험검증이 요구된다.

• 한국지진공학회논문집
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• 제7권4호
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• pp.31-37
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• 2003

본 논문에서는 오래된 원자력발전소의 내진검증과 관련한 USI A-46 문제의 해결에 사용될 수 있는 캐비닛의 내진보강방안에 대해 연구하였다. 캐비닛 구조물의 동적거동특성을 파악하기 위하여 3종류의 모델링을 수행하였고 그 결과를 비교하였다. 또한 ICRS(In Cabinet Reponse Spectrum)의 저감을 위하여 1) 보강프레임, 2)감쇠기 설치, 3) 동조질량감쇠기 등 세 가지 내진보강방안에 대하여 구조물의 응답을 산정하였다. 해석결과, 가새보강 및 감쇠기를 설치하는 보강방법에서는 보강전의 구조물보다 큰 ICRS가 얻어지는 경우가 발생해 보강시 많은 주의가 요구된다. 동조질량감쇠기의 사용은 좋은 제진효과를 보였으나 실구조물과 정확한 진동특성을 반영한 모델의 작성이 중요한 것으로 판단되었다.

• Nuclear Engineering and Technology
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• 제55권12호
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• pp.4617-4627
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• 2023

Public perception of benefit over risk is the de facto factor in planning, construction, operation, halting, or phase-out of a nuclear power plant in any country. Even if there are multiple pathways of perceiving risk/benefit among different stakeholders, the perception of nuclear and non-nuclear groups needs to be individually tracked to help understand sectoral influence. Related studies were basically performed between the STEM (Science, Technology, Engineering, and Mathematics) and non-STEM groups. However, there are no such studies between the nuclear and non-nuclear groups. This study investigated the risk-benefit perceptions between the nuclear group (N = 102) and the non-nuclear group (N = 467) using survey data to measure their stake and identify the underlying factors by validating the hypotheses, through descriptive analysis, and structural equation modeling (SEM). Results showed that risk perception is significantly high in the non-nuclear group (as the P-value is > 0.001 to <0.01) while the benefit perception is slightly low in the nuclear group (as the P-value is > 0.01 to <0.05). The non-nuclear group was significantly influenced by risk perception due to a lack of involvement in nuclear activities. Notably, the nuclear group is less interactive in disseminating nuclear energy benefits to the non-nuclear group. Surprisingly, misperceptions and lack of confidence about the benefits of nuclear energy also exist in the nuclear group. The study emphasizes debunking nuclear myths in the nuclear and non-nuclear groups through meaningful interactions and demands effective public awareness-building programs by competent authorities for the growth of the nuclear industry.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2012년도 제38회 춘계학술대회논문집
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• pp.219-224
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• 2012

본 연구에서 중형 상용민간항공기 추진진기관인 분리형 노즐을 갖는 2 스풀 터보팬 엔진인 BR715-56의[1] 정상 성능모델을 구성 및 탈설계점 성능해석이 상용코드인 MATLAB/SIMULINK를[2] 이용하여 엔진성능특성과 엔진진단을 위해 수행되었다. 먼저 팬, 고압압축기, 고압터빈, 저압터빈 구성품 성능 맵들이 축척방법을 이용하여 유사성능 맵들을 축척하여 생성되었고 다음 탈설계점 성능모사 프로그램이 구성품들 간 유량과 일 조화에 의해 구성되었다. 모델은 용이한 정상 및 동적 모사와 사용자 편의의 장점을 갖는 SIMULINK 프로그램을 이용하여 개발되었다. 제안한 모델에 의한 탈설계점 해석 결과들은 다양한 작동 조건들에서 GASTURB에 의한 해석 결과들과 잘 일치함이 확인 되었다.

• International journal of advanced smart convergence
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• 제4권1호
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• pp.45-53
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• 2015

This paper is proposed mathematical load modelling based on system identification approach of energy consumption of residential air conditioning. Due to air conditioning is one of the significant equipment which consumes high energy and cause the peak load of power system especially in the summer time. The demand response is one of the solutions to decrease the load consumption and cutting peak load to avoid the reservation of power supply from power plant. In order to operate this solution, mathematical modelling of air conditioning which explains the behaviour is essential tool. The four type of linear model is selected for explanation the behaviour of this system. In order to obtain model, the experimental setup are performed by collecting input and output data every minute of 9,385 BTU/h air-conditioning split type with $25^{\circ}C$ thermostat setting of one sample house. The input data are composed of solar radiation ($W/m^2$) and ambient temperature ($^{\circ}C$). The output data are power and energy consumption of air conditioning. Both data are divided into two groups follow as training data and validation data for getting the exact model. The model is also verified with the other similar type of air condition by feed solar radiation and ambient temperature input data and compare the output energy consumption data. The best model in term of accuracy and model order is output error model with 70.78% accuracy and $17^{th}$ order. The model order reduction technique is used to reduce order of model to seven order for less complexity, then Kalman filtering technique is applied for remove white Gaussian noise for improve accuracy of model to be 72.66%. The obtained model can be also used for electrical load forecasting and designs the optimal size of renewable energy such photovoltaic system for supply the air conditioning.

• 동력기계공학회지
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• 제13권6호
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• pp.95-101
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• 2009

The generator for gas turbine power generation consists of the rotor which generates magnetic field, the winding coil which is the path for the field current and the wedge and retaining ring which prevents the radial movement of the coil. Relatively severe deformation was observed at the coil end section during the inspection of the generator for peaking-load operation, and the thermal-electricity and the centrifugal force were evaluated by the simple modeling of the windings to find the cause. But the simulation stress was not sufficient to induce the coil plastic deformation. The analysis result seems to be applicable to the base-load generators which runs continuously without shut down up to a year, but there had been more deformation than simulated for the generator which is started up and shut down frequently. The cause of the coil deformation was the restriction of the expansion and shrinkage. The restriction occurs when the winding coil shrinks, and the stress overwhelms the yield stress and cause the plastic deformation. The deformation is accumulated during the start-ups and shut-downs and the thermal growth occurs. The factors which induce the coil restriction during the expansion and shrinkage should be reduced to prevent the unallowable deformation. The resolutions are cutting off the field current earlier during the generator shut-down, modifying the coil end section to remove the stress concentration and making the insulation plate inserted between the coil end section and the retaining ring have the constant thickness.

• 대한환경공학회지
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• 제28권1호
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• pp.97-103
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• 2006

본 논문은 미세 오존 출력을 얻을 수 있는 자동제어형 오존발생장치의 제어기법을 제시하고, 또한 무성방전에 의한 오존발생장치의 유입공기를 공극에서 저온인 $2^{\circ}C$까지 냉각 하여 포화 확산도가 높은 고밀도 탈취용 오존을 발생시킬 수 있는 기법을 제시한다. 고주파수의 오존방전 노이즈에 의한 전원파형의 불량화를 보상하기 위해서 디지털 궤환 제어시스템을 구성하고, 방전관의 등가 커패시터의 전압과 전류를 검출하여 2중의 제어루프를 설계한다. 부하변동에 따르는 과도상태 응답특성을 개선하고 제어기의 연산 지연시간을 보상하기 위하여 연산시간을 전원장치 플랜트의 고유한 파라미터로 가정하여 플랜트모델에 포함시켜 모델링한다. 제안된 오존 발생기는 고농도 고효율의 오존방전 시스템의 입력전원에서 고주파방전노이즈가 제거되어 정현적으로 되며 2배 이상의 안정된 오존출력을 얻는 것을 실험적으로 입증한다.

• 한국대기환경학회지
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• 제34권5호
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• pp.687-696
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• 2018

In order to develop effective emission abatement strategies for coal-fired power plants, we analyzed the shutdown effects of coal-fired power plants on $PM_{2.5}$ concentration in June by employing air quality model for the period from 2013 to 2016. WRF (Weather Research and Forecast) and CMAQ(Community Multiscale Air Quality) models were used to quantify the impact of emission reductions on the averaged $PM_{2.5}$ concentrations in June over Chungcheongnam-do area in Korea. The resultant shutdown effects showed that the averaged $PM_{2.5}$ concentration in June decreased by 1.2% in Chungcheongnam-do area and decreased by 2.3% in the area where the surface air pollution measuring stations were located. As a result of this study, it was confirmed that it is possible to analyze policy effects considering the change of meteorology and emission and it is possible to quantitatively estimate the influence at the maximum impact region by utilizing the air quality model. The results of this study are expected to be useful as a basic data for analyzing the effect of $PM_{2.5}$ concentration change according to future emission changes.