ICONE23-1629 NUMERICAL ANALYSIS OF DROPLET IMPINGEMENT EROSION CONSIDERING THE FLUID/MATERIAL FACTORS

Abstract

The wastage by Liquid Droplet Impingement (LDI) in piping system of nuclear power plant is becoming great problem in recent years because of high aging operation. In this study, by using our original fluid/material two-way coupling numerical method which considers reflection and transmission on the fluid/material interface, high-speed LDI on material surface is simulated. There are the various fluid/material factors in LDI. In this study, the influence of droplet diameter, impingement velocity, and the condition of material surface on LDI is investigated. First, in order to consider the basic condition, the LDI on dry and flat surface is analyzed. Secondly, in an actual power plant, because there may be humidity inside a steam pipe line and the material surface is wet, the LDI on wet surface is analyzed. Additionally, it is thought that the pipe inner surface is not a completely flat surface because of processing or repeating LDI. To make sure that the effect of the rough surface, the LDI on pitted surface is analyzed. From the numerical results, it was shown that the wetness of material surface has an effect on decrement and the roughness of material surface has an effect on increment of maximum equivalent stress in the material. Moreover, the evaluation of present numerical results has become in the range of the value of the existing prediction formula and experiment.