| Summary: | 博士 === 國立清華大學 === 核子工程與科學研究所 === 103 === Computational fluid dynamics (CFD) is increasingly being used in nuclear reactor safety (NRS) analyses to describe safety-relevant phenomena occurring in the reactor coolant system in greater detail. The majority of this paper is to investigate the CFD modeling and assessment for numerically simulating the thermal–hydraulic characteristics within the fuel rod bundle using CFD methodology. And this characteristic for mixing-vane grids of heat transfer capability and completeness has a great influence. The three-dimensional partial can reasonably reproduce distribution, it cannot simulate for traditional analysis tools and CFD can contribute at this ability.
This paper presents the results of numerical issues such as mesh refinement, wall treatment, are applied to the prediction of turbulent flow. The performance of various turbulence models are evaluated by calculation of the Nusselt number distribution in a fuel bundle. Comparison between numerical and experimental results of lateral and axial distributions for the Nusselt number obtained via turbulence model without near-wall functions is not sufficiently good, while agreement is found the realizable k-ε model with near-wall functions accurately predicts, for locations close to the support grid. As a result of this study, we have been able to determine the most appropriate turbulence models and the best enhanced wall treatment for modeling reactor coolant systems. Therefore, parallel tests or assistance are necessary for the regulator staff to review the license issues for CFD investigating the localized thermal-hydraulic characteristic within mixing-vane grids.
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