Pressure drop characteristics on flow holes with converging shapes in the bottom plate of fuel assembly

The purpose of this paper was to analyze the pressure drop characteristics in flow holes with converging shapes to find optimum design of the bottom plate. The pressure drop fluid was affected by the degree and depth of chamfering on holes in the bottom plate. Computational Fluid Dynamics (CFD) was performed to conduct a parameter study in chamfering effects of holes in the bottom plate. The four case basic models and two optimum case models were analyzed by CFD and the experiments had been carried out for two models which IC and OPTICOC2 of six models. Calculated results of two optimum candidates indicated that the pressure drop decreases up to 40 percent at the plate region. It was clear in agreement with the results of the experiments considering the difference of circumference between experimental investigation and CFD. As a result of this study, it was expected that the candidate of analytical models were to be applicable for the actual fuel assembly (bottom plate) development in the future and also induced to reduce 2 ∼ 3 percent of total pressure drop for the whole fuel assembly. (author)