Fluid Structure Interaction Analysis of a Surge-line Using Coupled CFD-FEM

The mixing with different-temperature water in the pressurizer surge line may result in thermal stratification, then the significant deformation of the solid structure due to different thermal expansion at different parts of the structure perhaps occur, which will be a threat for the plant safety. To better understand the coupling mechanism, the corresponding characteristics in a pressurizer surge line is analyzed using CFD software (ANSYS CFX) and FEM solver, (ANSYS MECHANICAL). The fluid temperature distribution is calculated first, then the corresponding thermal and mechanical characteristics are analyzed. It is found that a large steady state stress present at the edges of the main pipe and the pressurizer, the consequent deformation showed large displacement at the center of the surge line.