压水堆下腔室流量分布数值分析

建立了压水堆下腔室流场的三维数值计算模型，计算了不同环腔厚度和环腔内冷却剂速度条件下，下腔室内冷却剂的流场，分析了环腔厚度和环腔内冷却剂速度对下腔室流向堆芯的流量分布的影响。入口速度不同或环腔厚度不同，在下腔内冷却剂流动形成漩涡的位置、大小和流动速度均会发生改变，导致通过流量孔板通孔的流量分布不同。入口速度较低时，流量孔板上所有通孔的流量分布比较均匀，在平均值附近波动，流量最高的通孔小组出现在边缘处；入口速度较高时，流量明显地呈现出中心高边缘低的特点。通孔小组的流量最大值随着环腔厚度增加由孔板的中心向边缘移动。

Numerical Analysis on Mass Flow Rate Distribution of PWR Lower Plemum

Three dimensional computational model of the fluid flow in the lower plenum of a pressure water reactor was built up. The flow field in the lower plenum was computed under the condition of different annular downcomer thickness and coolant velocities. The effect of the annular downcomer thickness and coolant velocity on the mass flux distribution of the coolant flowing from the lower plenum to the reactor core was also investigated. If the annular downcomer thickness or the inlet velocity is different, the location, scale and velocity of coolant eddies will vary, and the mass flow rate distribution at the holes in the flow plate will be different. At lower inlet velocity, the mass flow rate of every hole group on the flow plate fluctuates near the average value and the hole group of maximum mass flow rate locates at the center of the flow plate. While the mass flow rate decreases from the center to the edge of the flow plate at higher inlet velocity. The hole group of maximum mass flow rate moves from the center to the edge of the flow plate with the thickness of the annular downcomer increasing.