间距对快堆燃料组件迷宫密封结构性能影响的数值模拟

本文采用计算流体动力学（CFD）方法针对直角梯形齿迷宫密封结构进行了三维数值模拟，对比研究间距对密封性能、流场分布、压力场分布、流速控制的影响，并在最佳间距尺寸下分析了偏心度对密封性能的影响。结果显示：扩大迷宫密封结构间距可有效减少漏流量、提高密封性能，并实现较好的流速控制，还可明显改善近壁面处的流动性能，强化对燃料组件外壁面的冷却；当间距超过3.02 mm时，密封性能提高有限，说明间距超过一定限值时，不能继续通过扩大间距提高迷宫密封结构密封性能，需在结构设计与工程应用中选择合理的间距尺寸；偏心现象导致迷宫密封结构流域内流速、压力分布不均匀，且随偏心度的增大不均匀现象有扩大的趋势，不仅对密封性能产生不利影响，还使得燃料组件振动加剧。

Numerical Simulation of Effect of Spacing on Performance of Labyrinth-seal Structure of Fast Reactor Fuel Assembly

The computational fluid dynamics (CFD) was used to simulate the labyrinth-seal structure of right angle trapezoid with different spacing in this paper. Then, the comparative research was conducted including the effects of spacing on sealing performance, flow field distribution, pressure field distribution and control of flow velocity, and the effect of eccentricity on sealing performance was analyzed at the optimal spacing. The results show that increasing the spacing of the labyrinth-seal structure can effect ively reduce the leakage flow, improve the sealing performance, achieve better control of flow velocity and can also significantly improve the flow performance near the wall surface and enhance the cooling of the outer wall surface of fuel assembly. As the spacing exceeds 3.02 mm, the improvement of sealing performance is very limited, indicating it is impossible to continue to improve the sealing performance of the labyrinth-seal structure by increasing the spacing when the spacing exceeds a certain limit. It is necessary to select the reasonable spacing in structural design and engineering application. The eccentricity leads to the imbalance of flow velocity and pressure distribution in the flow region, and as the eccentricity increases, the unevenness tends to expand, which not only adversely affects the sealing performance, but also exacerbates the vibration of the fuel assembly.