蒸汽发生器致畸变入流对核主泵流动性能的影响

为了探究由蒸汽发生器（SG）引起的畸变入流对核主泵（RCP）流动性能的影响，采用计算流体力学方法，建立核主泵与下封头的联合计算模型；利用多参考坐标系模型和滑移交界面技术，开展运行工况下的全三维稳态和瞬态数值模拟；采用入流畸变度和平均偏流角公式定量表征畸变入流的流场速度分布，通过正则化螺旋度法捕捉核主泵叶轮的涡流流动特征. 研究结果表明：与均匀入流相比，畸变入流复杂化了核主泵进口流场，导致核主泵的湍动能和湍耗散增大，降低了主泵的水力效率；在泵的进口流场形成了明显的非对称分布的涡核区域，引起叶轮各流道流态产生差异，造成叶轮内部压力和速度分布不均；导致各流道流量分配不均，加剧叶轮受载波动；降低其运行的稳定性和安全性.

Influence of distorted inflow caused by steam generator on flow properties of reactor coolant pump

A united model for the reactor coolant pump (RCP) and the channel head was generated by using the method of computational fluid dynamic, in order to analyze the influence of the distorted inflow caused by the steam generator (SG) on the flow property of RCP. Three-dimensional steady and transient numerical simulations in normal operating conditions were performed by using multiple frames of reference and sliding interface technology. The velocity distribution of distorted inflow was quantitatively characterized by inflow distortion degree and mean drift angle, and the regularization helicity method was used to capture the flow characteristics of vortex core for the impeller of RCP. Results show that with the comparison of uniform inflow, the inflow field of the RCP is complicated by the distorted inflow, and the turbulent kinetic energy and turbulent eddy dissipation are increased while the hydraulic efficiency of the RCP is decreased. Obvious asymmetric vortex core regions form in the RCP inlet, causing differences between the flow patterns of the impeller flow channels, and then causing the non-uniform distribution of the pressure and velocity within the impeller. Furthermore, due to the distorted inflow, the flow distribution of each flow channel is uneven, increasing the load fluctuation. The distorted inflow has an adverse effect on the RCP, reducing the stability and safety of the operation of RCP.