Study on LDI erosion using two-phase flow analysis with droplet model

Evaluation of wastage rate for nuclear power plant piping is important in maintaining plant reliability and safety. The two commonly well known causes of pipe wastage are liquid droplet impingement erosion (LDIE) and flow accelerated corrosion (FAC). This study is to evaluate the wastage rate of pipe wall and to measure the loss of mass caused by LDIE. LDIE often occurs at downstream of cornet of pipe or orifice. A high speed rotating disk and water jet is used to perform LDIE phenomena. In this study, based on the liquid droplet impinging model, Two-Phase Analysis was conducted with the TRAC code and FLUENT code. The TRAC code was used by analyze the total drain line, and FLUENT code was used to analyze the 3 dimensional steam flow and droplet trajectory. After the analysis, visualized flow test was conducted with two-phase flow of high void fraction supplied from a high pressure steam supply system. The steam velocity distribution was measure and droplet diameters were measured by LDV and high speed flush system. The test data were used to evaluate the maximum erosion rate and volume decreasing rate by using the droplet model. (author)