快堆燃料组件棒束通道内流动和传热现象分析与研究

利用三维计算流体力学软件CFX 12.0对由7根带螺旋状定位绕丝的燃料棒组成的快堆燃料组件典型棒束通道内的流动和传热现象进行了数值模拟。模拟得到不同Re下的压降系数曲线与Nu曲线，并将计算结果与经验公式的计算结果进行了比较，两者符合较好。研究了组件内3类典型子通道的横向流交混效应，分析了3类典型子通道的横向流分布特点，发现角子通道横向流交混强度沿轴向波动较大，而3类子通道的横向流交混强度均存在周期性。研究了中心燃料棒壁面上3个截面的局部换热效应，发现在燃料棒与绕丝接触处传热效果最差，在事故分析时应重点关注。

Analysis and Investigation on Flow and Convective Heat Transfer Phenomena of Fast Reactor Fuel Bundle

Commercial CFD code CFX 12.0 was used as an approach to investigate the flow and convective heat transfer phenomena of a typical 7-pin fuel bundle with wrapped wire. The pressure drop coefficient and Nusselt number under different Re were obtained, and the simulation results are in good agreement with empirical correlations. The transverse flow effects in three kinds of typical subchannels were investigated, and its features were analyzed. The results show that the corner channel’s transverse flow intensity varies heavily along the axial direction, and the transverse flow intensities in three typical subchannels show periodic feature. The local Nusselt number distribution on three cross sections of the central rod surface was also analyzed. The results show that the minimum local Nusselt number occurs close to the contact location of wire and rod, which means that the convective heat transfer condition is the worst in such area, and the special attention in accident analysis is deserved.