核主泵动静叶栅内部非定常流动及其激励机制

The unsteady flow and exciting force in the reactor coolant pump are the main internal causes of the unit performance deterioration, flow-induced vibration, stress deformation and the fatigue failure of the key flow part, at the same time, it affects the operational reliability of the reactor coolant pump. Based on the MIGA multi-island genetic algorithm, I-SIGHT integrated optimization platform is used to realize regulation of multi-parameter and global optimization of reactor coolant pump. Based on the k-ω SST DDES model, the regularization helicity, Q criterion, flow field diagnosis and high-speed camera technology are applied and combine the numerical and experimental method to reveal the unsteady flow structure and the generation mechanism in the rotor/stator cascades of the reactor coolant pump. A high precision numerical prediction method for wall pressure pulsation of reactor coolant pump is established, and the model test of pressure fluctuation is carried out to reveal the amplitude and frequency characteristics of load distribution of rotor/stator cascades and wall pressure pulsation, frequency characteristics of the axial and radial exciting force on impeller. Three kinds of impeller annular seal structures of reactor coolant pump are designed, dynamic characteristic coefficients in different seal are solved by using rotor dynamics method of vortex-motion and the interactive mechanism of eccentric clearance flow to pressure and stiffness characteristics are revealed. Based on the fluid-structure coupling method to clarify the influencing mechanism of sealing structure on deformation and stress distribution of reactor coolant pump key flow part, to reveal the influence of some dimensionless parameters on friction coefficient and vortex ratio of sealing structure and to establish the influencing mechanism of sealing clearance flow on impeller vortex and negative direct stiffness. As a result, which provides the basic theoretical support and experimental data for the development of the high reliability reactor coolant pump.

核主泵内非定常流动及其激励力是引起机组性能劣化、流激振动、过流部件形变和疲劳的主要内因，影响泵运行可靠性。基于MIGA多岛遗传算法，应用I-SIGHT集成优化平台实现核主泵多参数调控和全局寻优，构建动静叶栅水力协同优化方法；基于k-ω SST DDES模型，应用正则化螺旋度、Q准则、流场诊断和高速摄像技术，通过数值和试验揭示动静叶栅内非定常流动与产生机理；建立核主泵压力脉动数值预测和测试方法，揭示动静叶栅叶片载荷分布和壁面压力脉动、叶轮轴向和径向激励力的幅频特性；设计3种密封结构，基于涡动转子动力学方法求解不同密封结构的动力特性系数，研究偏心间隙流对密封间隙压力特性和刚度特性的影响机理；基于流固耦合方法，阐明密封结构对过流部件形变和应力分布的影响机制，获得密封参数对密封结构摩擦系数和涡动比的影响规律，揭示密封间隙流对叶轮涡动和负直接刚度的影响机理。为高可靠性核主泵发展提供理论支撑。

在国家自然科学基金“核主泵内部动静叶栅非定常流动及其激励机制”（No.51866009）资助下，面向“华龙一号”核主泵及其反应堆一回路系统的关键技术问题，围绕核主泵水力性能的高精度非定常数值模拟方法、核主泵口环密封动力学及其激励机制、反应堆一回路和核主泵之间相互影响规律等方面进行了系统研究。.首先，基于三种URANS-LES混合模型，应用现代流动分析方法，实现核主泵水力性能的高精度计算，采用DDES模型的核主泵扬程、效率和轴功率预测值平均差的相对计算误差为1.18%、2.61%和0.65%，建立了核主泵动静叶栅水力协同设计方法，揭示了核主泵高精度非定常数值模拟时湍流模型的选择依据。.其次，揭示了核主泵动静叶栅叶片内部旋涡结构的演化过程，研发的核主泵高效水力模型，其试验与计算误差小于5%；研究表明螺旋密封结构方案，叶轮口环泄漏量和转子激励力显著下降30%。设计了3种密封结构，基于涡动转子动力学方法，研究了偏心间隙流对密封间隙压力特性和刚度特性的影响机理；基于流固耦合方法，获得了密封参数对密封结构摩擦系数和涡动比的影响规律，揭示了密封间隙流对叶轮涡动和负直接刚度的影响机理。.在此基础上，考虑反应堆一回路对核主泵叶轮入流特性的影响，建立了反应堆一回路三维简化模型，获得了反应堆一回路系统对核主泵叶轮入流特性的影响规律；基于能量平衡原理构建了反应堆一回路三维闭式系统的阻力调控方法，实现了卡轴事故工况下主泵与反应堆动力系统的瞬态流动的再现，试验表明该算法的相对计算误差不大于10%。.综上所述，项目构建了核主泵水力模型的高精度非定常数值计算方法，提出了反应堆一回路系统瞬态停泵水锤波计算方法，实现了反应堆一回路闭式三维模型建立与阻力调控技术，获得了核主泵卡轴事故过渡过程瞬态压力波和水力载荷的数值结果，为反应堆一回路闭式系统事故安全性分析评价提供了理论方法和基础数据，从而保证反应堆一回路的安全可靠运行。