事故工况下AP1000核主泵惰转模型优化设计

发布时间：2018-07-14 12:10

【摘要】：核主泵是核电站冷却回路系统中重要组成部分,也是实现国产化核电力关键设备之一。在发生断电事故时,由于机组转动惯量储存的能量,系统核主泵会继续惰转运行一段时间。如果惰转过渡过程时间过于短暂,核主泵转速快速下降到最低水平,使反应堆产生的热量不能及时排出,容易造成堆内氢气集中现象,严重时发生爆炸事故。因而,惰转过渡过程过渡过程时间长短是核主泵安全评价的重要内容。本文通过理论分析、数值模拟和试验研究三者相结合的方法,对核主泵惰转特性进行研究,从水力性能和力矩性能两方面优化惰转过渡过程,分析不同转动惯量和管路阻力对惰转过渡过程的影响,探索在惰转过渡过程中不同转动惯量对核主泵叶轮内部流动和动力特性的影响,在此基础上根据叶轮几何参数建立惰转过渡过程数学模型。主要研究内容和成果如下:1、根据核主泵机组转动惯量储存的能量在惰转过渡过程中的分配,提出以优化核主泵的水力性能为目标,以此来减小惰转过渡过程中叶轮中的能量损失,延长惰转时间;查阅大量文献,挑选叶轮进出口直径、叶轮出口倾斜角、叶片数、叶片包角、叶片出口宽度、叶片出口角及面积比八个几何参数作为优化参数,进行正交试验设计。2、利用Pro/E软件和CFD软件完成不同叶轮几何参数组合模型的三维造型和外特性计算,通过对数值模拟计算结果进行相关性分析、偏相关分析和通径分析,得出影响水力性能的主要几何参数及叶轮几何参数对核主泵水力性能的直接和间接作用;结合偏相关分析和通径分析的结果,以效率为目标性能,选择最优叶轮几何参数组合为:γ=23o、β_2=30o、φ=115o、Z=5、b_2=200mm、D_2=770mm、D_0=555mm、Y=1.002,通过对最优结构参数组合的叶轮进行试验验证,相比原叶轮惰转时间有所延长。3、通过搭建核主泵水力样机惰转试验台,分析转动惯量和管阻对惰转过渡过程的影响。通过试验结果可知:在惰转过渡过程中,对扬程变化梯度影响较大,对流量变化梯度较小,转速变化梯度在两者之间;且管阻和转动惯量对惰转过渡过程中有着不同的影响:管阻对惰转过渡过程中转速影响不大,对流量和扬程有较大的影响;而转动惯量对惰转过渡过程中的转速、流量和扬程都有较大的影响。4、为了研究在惰转过渡过程中不同转动惯量对叶轮水力特性和动力特性的影响,利用MATLAB软件将不同转动惯量对应的转速和流量与时间的变化曲线拟合成对应公式作为CFX计算边界条件,进行惰转过渡过程非定常计算,通过计算结果可知:不同转动惯量对应叶轮水力特性和动力特性有较大的影响,转动惯量越大,对应叶轮水力特性和动力特性下降梯度越小,转动惯量越小,对应叶轮水力特性和动力特性下降梯度越大。5、结合正交试验和CFX数值模拟软件计算不同叶轮几何参数组合模型对应的六个惰转工况下的力矩系数结果,利用多元逐步分析法计算不同叶轮几何参数组合与力矩系数之间的关系,得到力矩系数与叶轮几何参数之间的回归方程及最优叶轮几何参数组合;运用主成分分析法建立惰转过渡过程中叶轮几何参数、转动惯量、转速和时间四者之间数学模型;通过Flowmaster搭建核主泵惰转模拟试验台来验证数学模型的正确性,结果表明:数学模型计算的惰转过渡过程中转速变化曲线和Flowmaster核主泵惰转试验台模拟的转速变化曲线之间的区别很小,说明数学计算模型对不同的叶轮几何参数的核主泵有很好的预测效果。6、通过计算水力优化模型和力矩性能优化模型的外特性和惰转特性,计算结果表明:水力优化模型通过提高设计点的水力性能来整体减小惰转过渡过程能量损失,提高惰转特性,而力矩性能优化模型将核主泵的高效区向小流量区域偏转来提高惰转特性;对比两者可知:力矩性能优化模型大于水力优化模型对惰转特性的提高幅度。
[Abstract]:The nuclear main pump is an important part of the cooling circuit system of the nuclear power plant. It is also one of the key equipment to realize the domestic nuclear power. In the event of power failure, the system nuclear main pump will continue to run lazly for a period of time because of the energy stored in the inertia of the unit. If the time of the transition process is too short, the speed of the nuclear main pump will fall quickly to the speed of the nuclear power plant. At the lowest level, the heat of the reactor can not be discharged in time, it is easy to cause the concentration of hydrogen in the reactor, and the explosion accident occurs seriously. Therefore, the time of the transition process of the inert transition process is an important content of the safety evaluation of the nuclear main pump. Through theoretical analysis, numerical simulation and experimental research, the three methods are combined to the nuclear owner. The characteristic of pump inert is studied. The effect of different inertia and pipe resistance on the inert transition process is analyzed from two aspects of hydraulic performance and torque performance. The influence of different rotational inertia on the internal flow and dynamic characteristics of the main pump impeller is explored in the process of inert transition, based on the geometry of the impeller. The main research contents and results are as follows: 1, according to the distribution of the energy stored in the inertia of the nuclear pump unit in the process of the inert transition, the aim is to optimize the hydraulic performance of the nuclear main pump, so as to reduce the energy loss in the impeller and prolong the idle time in the process of the inert transition. The diameter of the impellers, the inlet and outlet diameter of the impeller, the inclination angle of the impeller outlet, the number of blades, the blade angle, the blade outlet width, the exit angle and the area of the blade are compared with eight geometric parameters, and the orthogonal test is designed for.2. The three-dimensional modeling and external characteristic calculation of the geometric parameters combination model of different blade wheel are completed by Pro/E software and CFD software. Through correlation analysis, partial correlation analysis and path analysis, the main geometric parameters affecting the hydraulic performance and the direct and indirect effects of the impeller geometric parameters on the hydraulic performance of the nuclear main pump are obtained, and the optimal impeller geometric parameters are selected by combining the results of partial correlation analysis and path analysis. The number of combinations are: gamma =23o, beta _2=30o, Phi =115o, Z=5, b_2=200mm, D_2=770mm, D_0=555mm, Y=1.002. By testing the impeller of the optimal structural parameters, compared with the original impeller inert time, the effect of the inertia and pipe resistance on the inert transition process is analyzed. The results show that in the process of transition, the gradient of the head change has a larger influence, the gradient of the flow change is smaller, the speed change gradient is between the two, and the tube resistance and the rotational inertia have different effects on the inert transition process: the tube resistance has little influence on the speed during the inert transition, and has a great influence on the flow and lift. In order to study the influence of different rotational inertia on the hydraulic and dynamic characteristics of the impeller during the inert transition process, the dynamic inertia has a great influence on the speed, flow and head in the process of inert transition. In order to study the influence of different rotational inertia on the hydraulic and dynamic characteristics of the impeller during the inert transition process, the corresponding formula of the rotational speed, the flow rate and the time curve corresponding to the different rotational inertia is prepared by using the MATLAB software as CFX. The boundary conditions are calculated, and the unsteady calculation of the inert transition process is carried out. Through the calculation results, it is found that the different rotational inertia has a great influence on the hydraulic and dynamic characteristics of the impeller. The larger the moment of inertia, the smaller the gradient of the hydraulic and dynamic characteristics of the impeller, the smaller the moment of inertia, and the hydraulic and dynamic characteristics of the impeller. The greater the gradient of the gradient is.5, the result of the moment coefficient is calculated by combining the orthogonal test and the CFX numerical simulation software. The relationship between the geometric parameters combination of different impeller and the moment coefficient is calculated by the multivariate stepwise analysis method, and the back between the moment coefficient and the geometric parameters of the impeller is obtained. The combination of the regression equation and the optimal impeller geometric parameters; using the principal component analysis method to establish the mathematical model between the geometric parameters of the impeller, the rotational inertia, the rotational speed and the time in the process of the inert transition, and to set up a nuclear main pump inert simulation test rig by Flowmaster to verify the correctness of the mathematical model, and the results show that the inert transition of the mathematical model is calculated. The difference between the speed change curve of the process and the change curve of the Flowmaster core main pump is very small. It shows that the mathematical model has a good prediction effect on the nuclear main pump with different impeller geometric parameters. The calculation of the external and inert characteristics of the hydraulic optimization model and the torque performance optimization model is calculated by calculating the hydraulic optimization model and the torque performance optimization model. The results show that by improving the hydraulic performance of the design point, the hydraulic optimization model reduces the energy loss of the inert transition process and improves the inert transfer characteristic, while the torque performance optimization model turns the high efficient area of the nuclear main pump to the small flow area to improve the inert rotation characteristic. The increasing amplitude of the inert property.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM623

【参考文献】