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采用非结构化多面体网格和商业计算流体力学(CFD)软件对两类带有流动强化特征的定位格架对超临界水在反应堆堆芯子通道内流动及换热特性的影响进行数值研究。研究结果表明:定位格架对子通道内超临界水的换热影响显著;在定位格架内部,流通面积减小,流速增加,换热得以有效强化;阻流片型定位格架对子通道中心流体的阻挡和导流能够中和流动阻塞效应,强化其下游窄缝区的局部换热效果;交错叶片型定位格架能够在其下游产生漩涡流,加强相邻子通道间工质的热量和质量交换,强化局部换热;漩涡流也可能导致轴向速度损失,造成局部换热弱化,不利于反应堆的安全性;入口雷诺数Re对交错叶片型定位格架下游局部换热有较大影响。Re较高时,此类定位格架对子通道内局部换热的强化作用更为明显。
The influence of two kinds of positioning grids with flow enhancement on the flow and heat transfer characteristics of supercritical water in reactor core passage was investigated by using unstructured polyhedral mesh and commercial computational fluid dynamics (CFD) software. The results show that: the positioning grid has a significant effect on the heat transfer of supercritical water in the subchannel; in the positioning grid, the flow area decreases, the flow rate increases, heat exchange can be effectively strengthened; The blocking and diversion of the central fluid can neutralize the flow blocking effect and enhance the local heat transfer effect of the downstream narrow slot region. The staggered leaf-type positioning grid can generate eddy currents in the downstream and enhance the heat of working fluid between adjacent sub-channels And mass exchange, strengthen the local heat exchange; swirling flow may also lead to the axial velocity loss, resulting in weakening of the local heat exchange is not conducive to the safety of the reactor; inlet Reynolds number Re interlaced vane positioning grid downstream local heat exchange larger influences. When Re is high, the strengthening effect of such a locating grid on the local heat exchange in the sub-channel is more obvious.