基于控制体积法的圆管导热反演算法及工程应用研究

Research on Inversion Algorithm and Engineering Application of Circular Tube Heat Transfer Based on Control Volume Method

为准确评估管道热疲劳效应、减少因管道热疲劳导致核电厂机械设备故障失效事件,提出了一种快速求解圆管二维热传导反问题、间接获取管道内部温度的方法。将半圆管划分为若干个控制体,列出时间上的常微分方程,通过时间和空间变量分离进行内部温度求解。该方法利用了空间滤波和时间线性拟合,不需要假设初值和迭代计算,可以在不破坏管道的情况下快速获取内壁温度。同时,利用数值和试验验证了该算法的准确性和精度。在此基础上,对时间步长、测点布置数量等方面进行深入分析,给出了离线和在线监测工程应用场景解决方案。该方案已经在“华龙一号”机组上开展实际工程应用。其应用结果为该方法在后续批量化的“华龙一号”机组建设提供示范参考。同时,该方法也可用于在运核电厂高温管道的热疲劳分析,为核电厂老化延寿提供数据支持,提高了核电厂的经济性。

In order to accurately evaluate the thermal fatigue effect of pipes and reduce the failure events of mechanical equipment in nuclear power plants caused by thermal fatigue of pipes,a fast method for solving the inverse problem of two-dimensional heat conduction of circular pipes and indirectly obtaining the internal temperature of pipes is proposed.The semicircle is divided into several control bodies,the ordinary differential equations in time are listed,and the internal temperature is solved by separating time and space variables.By using spatial filtering and time linear fitting,the method do not need to assume initial values and iterative calculation and can quickly obtain the inner wall temperature without damaging the pipeline.At the same time,the accuracy and precision of the algorithm are verified by numerical and experimental results.On this basis,the time step and the number of measuring points are deeply analyzed,and the solutions of offline and online monitoring engineering application scenarios are given.The scheme has been applied in“HRP1000”.The application results can provide a demonstration reference for the construction of“HRP1000”in the future.At the same time,this method can also be used for thermal fatigue analysis of high temperature pipelines in operation of nuclear power plants,which can provide data support for aging and life extension of nuclear power plants and improve the economy of nuclear power plants.