Prediction of possible wear sites on the shell wall of feedwater heater due to droplet impingement using CFD models

Severe wall thinning on the feedwater heaters (FWHs) shell may cause a leak on the wall, which will result in power plant derating or shutdown, or even in personal fatalities. Therefore, it is crucial to prevent the occurrence of leak on the shell wall of FWHs. The most useful method to decrease the leakage possibility is to measure the wall thickness of FWHs during plant outage. Then, the staff can take action in advance to remedy the severe wall thinning regions. In this paper, a methodology is proposed to qualitatively predict the distributions of severe wear sites on the FWH shell wall. This methodology includes the Eulerian/Lagrangian droplet flow model and the droplet impingement erosion model. This computational fluid dynamics (CFD) model can simulate the three-dimensional distribution of steam flow and the rebound characteristics of droplets within the FWH shell. Coupled with these flow characteristics, an appropriate indicator derived from the droplet impingement erosion model, is used to predict the severe wear sites on the FWH shell wall. The predicted wear sites on the shell wall correspond well to the plant measured ones. Based on this good agreement, the methodology proposed in this paper can help construct a monitoring project of wall thickness measurement for FWHs of power plants, especially in scheduling the measuring ranges on the shell wall.