蒸汽发生器换热管流量分配及其对核主泵入口流场的影响

Flow Distribution of Heat Exchanger Tubes in a Steam Generator and Its Effect on Flow Field at Entrance of Reactor Coolant Pump

为研究蒸汽发生器(SG)换热管流量分配及其对反应堆冷却剂泵(RCP)入口流场的影响,进行了蒸汽发生器的缩尺模型冷态实验,并以实验获得的数据为SG下封头的入流条件,对SG下封头进行数值建模,并采用计算流体力学(CFD)方法对其进行了三维流场计算。结果表明:SG换热管存在较严重的流量分配不均,SG入口管会对其所正对部分的换热管的流量分配产生较大影响,使该部分流量增大,即形成高速区,而高速区周围会形成相对的低速区甚至回流区;在小流量时,换热管的沿程损失将对换热管的流量分配起主导作用;SG换热管内的不均匀流量分配会使SG出口管处的轴向速度更加紊乱,即在核主泵入口产生更加严重的入流畸变。

For the study of steam generator（SG） heat exchange tube flow distribution and its effect on the reactor coolant pump（RCP） entrance flow, the scale model experiment in the cold state of the SG was conducted. The experimental data was the new inflow condition of the SG channel head. The three-dimensional flow field of the SG channel head was calculated by CFD method. The results show that the SG heat exchange tubes have serious uneven flow distribution. The SG entrance will have a greater impact on the flow distribution of the heat exchange tube, especially the tubes toward the entrance. The partial flow rate increases and the formation of high speed creates a relatively low velocity zone and the recirculation zone around itself; when the flow rate is small, the distance head of the heat exchange tube plays a leading role; the uneven flow distribution in the heat exchanger tubes of the SG will cause the axial velocity at the outlet of the SG to be even more turbulent.