Simplification of 3D transient heat conduction by reducing it to an axisymmetric heat conduction problem and a new inverse method of the problem solution

摘要

Most IHCP-solving methods available in literature are formulated for simple-shaped bodies and cannot be applied to complex geometries. In this work, the 3-D problem is simplified to an axisymmetric analysis. If the nozzle diameter is not much smaller than the diameter of the cylindrical component, a corrected axisymmetric model is proposed. Next, a method is presented for solving the axisymmetric IHCP in a complex domain. It is based on the control volume finite element method. Based on temperature transients measured on the outer surface, the temperature distribution is reconstructed by marching from the known to the unknown boundary. The developed method is applied for temperature identification in a cylindrical component with a nozzle. The presented algorithm is tested using measured temperatures generated from a direct solution. The transient temperature distribution obtained from the method presented in the paper is compared with the values obtained from the direct solution. The proposed method is also used to estimate the unknown boundary condition. The information about the heat transfer coefficient value makes it possible to describe the heat transfer phenomena occurring inside the component.The presented method makes it possible to optimize the power unit start-up and shutdown, contributes to a reduction in heat losses arising during the operations and enables extension of the power unit life. The method can be used in monitoring systems of both conventional and nuclear power plants. (C) 2019 Elsevier Ltd. All rights reserved.