• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.15-16
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• 2014

With the increasing trend in CFB(Circulating Fluidized Bed) boiler scale, the EHE(External Heat Exchanger) must be adopted to the large-scale boilers to recover insufficient heat transfer surface. In this study, the numerical analysis model for EHE in commercial 300MWe CFB boiler was developed with the inclusion of mechanistic model, which enables the heat transfer prediction. Finally, the calculated absorbed heat and derived heat transfer coefficient are evaluated through the verification with experimental data.

• 한국태양에너지학회 논문집
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• 제27권3호
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• pp.135-142
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• 2007

The model to predict flow duration characteristics and performance for small scale hydro power(SSHP) plants is studied to analyze the effects of rainfall condition. One existing SSHP plant was selected and performance characteristics was analyzed by using the developed model. The predicted results from the model developed show that the data were in good agreement with operational results of existing SSHP plant. The results show that both the scale parameter and the shape parameter have large effects on the performance of SSHP sites. And also it was found that the model developed in this study can be a useful tool to predict the performance of SSHP sites.

• 한국압력기기공학회 논문집
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• 제8권1호
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• pp.1-7
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• 2012

A PHE (Process Heat Exchanger) is a key component required to transfer heat energy of $950^{\circ}C$ generated in a VHTR (Very High Temperature Reactor) to the chemical reaction that yields a large quantity of hydrogen. A small-scale PHE prototype made of Hastelloy-X is being tested in a small-scale gas loop at Korea Atomic Energy Research Institute. In order to properly evaluate the high-temperature structural integrity of the small-scale PHE prototype, it is very important to impose a proper constraint condition on its structural analysis model. For this effort, we tried to impose several constraint conditions on the structural analysis model and consequently fixed a proper and effective displacement constraints.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2001년도 춘계학술대회 논문집
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• pp.337-344
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• 2001

Some as-built drawings in national roadway bridges in Korea were examined. There are many bridge piers, whose aspect ratios are in the vicinity of 2.5. These columns are expected to do shear-flexure behaviour and have large scale effect between full and reduced scale model. In the study, full and 1/2 scale model tests on the shear-flexure behaviour columns were carried out. The seismic performance of existing bridge piers without seismic details were examined by Quasi Static Test

• 수산경영론집
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• 제31권2호
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• pp.133-153
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• 2000

During the last several decades, Korea has been regarded as one of the fastest growing economies in the world. However, the small size of national land has not met the vigorous demand for land necessary to develop economic infra-structures such as large-scale harbors airports and highways. In order to satisfy the growing demand for land, the Korean government and industry have implemented the national land development programs to reclaim land from the sea fur the several decades. It is certain that these land development programs have resulted in a lot of property disputes between fishermen and public project administrators. This paper is to develop a quantitative model to estimate compensation for damages or restriction of charted fisheries resulting from large-scale public projects. In this paper, the compensation model is derived by using cost-volume-profit analysis framework because the compensation for charted fisheries basically depends on the factors such as the costs, production volume, profit of charted fisheries damaged or restricted by public projects. The model shows that the compensation for damages or restriction of charted fisheries is determined by the average annual profit, damage duration period, and the degree of fishery damages. In addition, the degree of fishery damages measured by the ratio of lost profit to annual average profit turns out to be determined by the following factors: annul profit, unit variable cost, decrease in production volume, the rate of increase in variable cost, and a change in fixed cost. Furthermore, this parer discusses the nam issues related to practices and regulation of the compensation for fishery damages in the current Fishery Act of Korea and suggests some appraisal methods which will be able to lead to theoretically correct and fair compensation for fisheries damages resulting from large-scale public projects.

• 한국산업정보학회논문지
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• 제14권3호
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• pp.58-75
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• 2009

최근 국가 연구개발 과제의 성과물에 대한 실용화 또는 상업화 강화가 중요한 이슈로 떠오르고 있으며, 기술 실용화 관점에서 연구개발 과제를 체계적으로 관리할 수 있는 지원 도구에 대한 필요성이 높아지고 있다. 기존의 기술준비수준 모델은 기초 연구부터 실용화까지의 기술 개발 수준을 9개의 수준으로 나누어 각각의 수준에 대한 기준을 제시해 줌으로써 과제 관리를 위한 유용한 도구로 활용되어 왔다. 그러나 이 모델은 기술준비수준의 평가가 전문가에 의해 이루어져야 하며 구체적인 평가지표도 제시되어 있지 않기 때문에 다수의 과제로 구성된 국가 연구개발 사업에 적용하기에는 어려움이 있다. 따라서 본 연구는 델파이 기법을 활용하여 기존의 기술준비수준 모델을 대규모 국가 연구개발 과제에 적용할 수 있도록 각 수준에 대한 정의와 각 수준의 달성 여부를 결정하는 평가지표를 제시하였다. 본 연구에서 제시된 기술준비 수준 모델은 각 수준에 맞는 구체적인 평가기준을 제공함으로 대규모 국가 기술개발 과제의 연구개발에서 실용화까지의 전 과정을 관리하기 위한 도구로 적절하게 활용될 수 있을 것으로 기대한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1115-1122
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• 2011

Reinforced-Roadbed materials are usually composed of crushed stones. Repeated load application can induce deformation in the reinforced-roadbed layer so that it causes irregularity of track. Thus it is important to develop a prediction model of elastic modulus based on stress-strain relation under repeatitive load in order to investigate behavior of reinforced roadbed. The prediction model of elastic modulus of the material can be obtained from repeated triaxial test. However, a proper size of the sample for the test must be used. In this study, a large repeatitive triaxial test apparatus with the sample size of diameter of 30 cm and height of 60cm was adapted for performing test of the crushed stone reinforced-roadbed considering large particle size to get resilient modulus Mr. The obtained resilient modulus was compared to shear modulus obtained from mid size resonant column test. The sample size effect is somewhat large enough so that it is required to design a scale factor based on similarity law in order to use smaller samples for getting elastic modulus of the crushed stone reinforced-roadbed material. A scale factor could be obtained from this study.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2011년 춘계학술대회논문집
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• pp.407-413
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• 2011

VIC (Vortex-In-Cell) method for viscous incompressible flow is presented to simulate the wake behind a modified NACA16 foil. With uniform rectangular grid, the velocity in field is calculated using streamfunction from vorticity field by solving the Poisson equation in which FFT(Fast Fourier Transform) is combined with 2nd order finite difference scheme. Here, LES(Large Eddy Simulation) with Smagorinsky model is applied for turbulence calculation. Effective viscosity is formulated using magnitude of strain tensor(or vorticity). Then the turbulent diffusion as well as viscous diffusion becomes particle strength exchange(PSE) with averaged eddy viscosity. The well-established panel method is combined to obtain the irrotational velocity and to apply the no-penetration boundary condition on the body panel. And wall diffusion is used for no-slip condition numerical results of turbulent stresses are compared with experimental results (Bourgoyne, 2003). Before comparing process, LES(Large Eddy Simulation) SGS(Subgrid scale) stress is transformed Reynolds averaged stress (Winckelmans, 2001).

• 농업과학연구
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• 제40권3호
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• pp.243-252
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• 2013

This study was carried out to investigate safety evaluation of agricultural reservoirs due to raising the embankment. The seepage analysis and large-scale model test were performed to compare and analyze the pore water pressure(PWP), leakage quantity, settlement and piping phenomenon in the inclined core type and the vertical core type embankments. The PWP after raising the embankment showed smaller than before raising the embankment and the stability for piping after raising the embankment. The allowable seepage quantity and the allowable leakage for the steady state and transient conditions is within the range of safe management standard. After raising the embankment in the inclined core, there was no infiltration by leakage. For the vertical core, the PWP showed a large change by faster infiltration of pore water than in the inclined core. In a rapid drawdown, inclined core was remained stable but the vertical core showed a large change in PWP. Settlement after raising the embankment showed larger amounts of settlement than before raising the embankment. The leakage quantity before raising the embankment and the inclined core type showed no leakage. From the result, an instrument system that can accurately estimate a change of PWP shall be established for the rational maintenance and stabilization of raising the embankment for agricultural reservoirs.

• Journal of Electrical Engineering and Technology
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• 제8권6호
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• pp.1596-1604
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• 2013

Coordinating operation between large-scale wind power and thermal units in multiple time scale is an important problem to keep power balance, especially for the power grids mainly made up of large coal-fired units. The paper proposes a novel operation mode of multi-scale unit commitment (abbr. UC) that includes mid-term UC and day-ahead UC, which can take full advantage of insufficient flexibility and improve wind power accommodation. First, we introduce the concepts of multi-scale UC and then illustrate the benefits of introducing mid-term UC to the wind-coal intensive grid. The paper then formulates the mid-term UC model, proposes operation performance indices and validates the optimal operation mode by simulation cases. Compared with day-ahead UC only, the multi-scale UC mode could reduce the total generation cost and improve the wind power net benefit by decreasing the coal-fired units' on/off operation. The simulation results also show that the maximum total generation benefit should be pursued rather than the wind power utilization rate in wind-coal intensive system.