• Nuclear Engineering and Technology
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• 제41권9호
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• pp.1143-1156
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• 2009

The SPACE code that is based on a multi-dimensional two-fluid, three-field model is under development for licensing purposes of pressurized water reactors in Korea. Among the participating research and industrial organizations, KAERI is in charge of developing the physical models and correlation packages for the constitutive equations. This paper introduces a developed wall-to-fluid heat transfer package for the SPACE code. The wall-to-fluid heat transfer package consists of twelve heat transfer subregions. For each sub-region, the models in the existing safety analysis codes and the leading models in literature have been peer reviewed in order to determine the best models which can easily be applicable to the SPACE code. Hence a wall-to-fluid heat transfer region selection map has been developed according to the non-condensable gas quality, void fraction, degree of subcooling, and wall temperature. Furthermore, a partitioning methodology which can take into account the split heat flux to the continuous liquid, entrained droplet, and vapor fields is proposed to comply fully with the three-field formulation of the SPACE code. The developed wall-to-fluid heat transfer package has been pre-tested by varying the independent parameters within the application range of the selected correlations. The smoothness between two adjacent heat transfer regimes has also been investigated. More detailed verification work on the developed wall-to-fluid heat transfer package will be carried out when the coupling of a hydraulic solver with the constitutive equations is brought to completion.

• 한국자동차공학회논문집
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• 제16권1호
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• pp.64-70
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• 2008

Temperatures of engine head and liner depend on many factors such as spray and combustion process, coolant passage flow and engine related structures. To estimate the temperature distribution of engine structure, multi-dimensional computational fluid dynamics (CFD) codes have been mainly adopted. In this case, it is of great importance to obtain the realistic wall temperature distribution of entire engine structure. In the present work, a CFD-FEM coupling methodology was presented to address this demand. This approach was applied to a real large-size marine diesel engine. CFD combustion and coolant flow simulations were coupled to FEM temperature analysis. Wall heat flux and wall temperature data were interfaced between combustion simulation and solid component temperature analysis via translator by a commercial CFD package named FIRE by AVL. Heat transfer coefficient and surface temperature data were exchanged and mapped between coolant flow simulation and FEM temperature analysis. Results indicate that there exists the optimum cell thickness near combustion chamber wall to reasonably predict the wall heat flux during combustion period. The present study also shows that the effect of cell refining on predicting in-cylinder pressure during combustion is negligible. Hence, the basic guidance on obtaining the wall heat flux needed for the reasonable CFD-FEM coupling analysis has been established. It is expected that this coupling methodology is a robust tool for practical engine design and can be applied to further assessment of the temperature distribution of other engine components.

• 한국건설관리학회논문집
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• 제12권4호
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• pp.11-20
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• 2011

최근 국내 건설산업에서의 건설사업관리제도(CM: Construct Management)는 발주자의 관리능력의 보완 및 건설사업의 종합적 관리를 통한 사업 효율성 제고의 수단으로서 인지되고 있으며, 적용이 확대되고 있다. 기 제정 및 개정된 건설사업관리 업무지침은 수행업무에 대한 범위 및 절차의 내용이 각 업무의 정의 수준에 머물러있고, 세부 업무에 대한 구체성이 미흡하여 세부업무에 대한 수행계획을 세우는데 효과적이지 못하다는 문제점과 기 수행된 건설사업관리 사례에 대한 조사에 따르면 각 건설사업관리 용역사 별, 프로젝트별에 따라 별도의 업무지침에 따라 업무가 계획 수행되고 있다는 점에서 효과적이고 효율적인 건설사업관리를 위해서는 구체화, 표준화된 업무지침서 및 절차서의 필요성이 높은 것으로 조사되었다. 따라서 관련 문헌 및 국 내외에서 수행된 건설사업 사례의 업무지침서와 절차서를 바탕으로 건설사업관리자의 주요업무를 도출하고, 설문조사를 통해 얻은 결과를 분석하여 핵심업무를 도출함으로써 향후 건설사업관리 계약 및 업무 수행에서 실질적인 활용이 가능할 것으로 기대된다.