带定位格架的类三角形子通道内超临界水流动传热数值研究

Numerical Study on Flow and Heat Transfer of Supercritical Water in a Triangular Sub-channel with Grid Spacer

针对超临界反应堆类三角形子通道的传热和流动特性,数值研究了不同栅距比定位格架作用下子通道内超临界水的流动传热特性、二次流及流动阻力特性。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;不同栅距比下的壁面温度、换热系数的轴向分布都具有相同的趋势,定位格架附近壁面温度下降,换热系数上升;定位格架下游壁面温度分布不均匀,且不均匀程度随栅距比减小而更加明显;定位格架下游截面形成四个对称旋涡,栅距比较小时,二次流强度较大;不同栅距比堆芯子通道流动阻塞率不同,流动阻力随栅距比减小而增大。

For the heat transfer and flow characteristics of supercritical pressure water flowing in triangular sub-channels of a super critical reactor, the heat transfer and flow of supercritical pressure water flowing in the sub-channels with grid spacer were studied numerically in different lattice spacing ratios. And the flow resistance and secondary flow were also studied in this paper. The research results show that the grid spacer has great effects on the heat transfer characteristics of supercritical pressure water flowing in the sub-channels. The axial distribution of the wall temperature and the heat transfer coefficient are all the same trend at different lattice spacing ratios. The wall temperature drops near the grid spacer, at the same time, the heat transfer coefficient rises. The wall temperature distribution is uneven at the downstream area of the grid spacer. And the uneven degree is obvious at smaller lattice spacing ratio. Four symmetrical vortices are formed at the downstream area of the grid spacer in the sub-channels. The secondary flow intensity is relatively larger when the lattice spacing ratio is smaller. The flow blocking rate of sub-channels with grid spacer is different at different lattice spacing ratios. The flow resistance in the sub-channels is relatively larger when the lattice spacing ratio is smaller.