反应堆一回路对核主泵叶轮入流特性的影响

Influence of reactor primary circuit on inflow characteristics of reactor coolant pump impeller

为了研究反应堆一回路对核主泵(RCP)叶轮入流特性的影响,将蒸汽发生器(SG)、入口弯管、冷热段管道、核反应堆及RCP进行联合简化建模.基于CFD方法对其一回路进行流场计算分析,对比分析均匀入流条件下RCP数值计算结果与试验结果,可以发现,由数值模拟得到的扬程和效率误差均在5%以内,验证了数值计算方法的正确性.在反应堆一回路中采用多孔介质模型,通过泵特性曲线与管路特性曲线的动态匹配,使得闭式系统RCP流量与额定工况值相差0.998%,扬程相差3.76%,二者误差较小,从而实现了管路阻力的动静态调节.研究结果表明:入口弯管内流动的周向对称性被破坏,其压力和速度分布呈现不均匀分布,受弯管曲率的影响,在离心力作用下产生二次流动;与均匀入流工况相比,非均匀入流工况下RCP入口处形成了一对回旋方向相反的旋涡,速度和压力的对称分布特性被破坏,且沿周向和径向的轴向速度变化均大于平均速度的80%.因此,本研究建立的数值预测方法可以为研究反应堆一回路对RCP叶轮入流特性的影响提供理论依据.

In order to study the influence of the reactor primary circuit on inlet flow field characteristics of reactor coolant pump(RCP),the combined simplified modeling of the steam generator(SG),inlet elbow,cold and hot section pipes,nuclear reactor and RCP was carried out.CFD method was used to calculate the flow field of its primary circuit.Comparing the RCP numerical calculation results with the experimental results under the condition of uniform inflow,it can be found that the head and efficiency errors obtained by numerical simulation are within 5%,which verifies the correctness of the numerical calculation method.The porous medium model is adopted in the reactor primary circuit,and the dynamic matching of the pump characteristic curve and pipeline characteristic curve makes the RCP flow rate differ by 0.998%from the rated working condition value of the closed system,and the difference between head and rated working condition value is 3.76%.The two errors are small,so as to realize the dynamic and static adjustment of pipeline resistance.The results show that the circumferential symmetry of the flow in the inlet elbow is destroyed,and the distribution of pressure and velocity is non-uniform.Influenced by the curvature of the elbow,secondary flow is generated under the action of centrifugal force.Compared with the uniform inflow condition,a pair of vortices with opposite whirling direction are formed at the inlet of RCP under the non-uniform inflow condition.The symmetrical distribution characteristics of velocity and pressure are destroyed,and the variation of axial velocity along the circumferential and radial velocity is greater than 80%of the average velocity.Therefore,the numerical prediction method established in this study can provide a theoretical basis for studying the influence of reactor primary circuit on the inflow characteristics of the RCP impeller.