報告書番号

L10018

タイトル（和文）

液滴衝撃エロージョンによる減肉率の評価モデルの構築

タイトル（英文）

Proposition of Wall Thinning Rate Model for Liquid Droplet Impingement Erosion

概要 （図表や脚注は「報告書全文」に掲載しております）

発電プラントの運用・管理上重要な配管減肉現象の内，
蒸気流中の液滴によるエロージョン(液滴衝撃エロージョン(LDI))について，
実機プラントでLDIが生じやすい環境である湿り蒸気流においてLDIを模擬した実験を実施し，
液滴径や流速などの流動因子と減肉量との相関を明らかにすると共に，
既存の減肉モデルの適用性の確認・新たな減肉モデルの提案を行った．

概要 （英文）

Liquid droplet impingement erosion (LDI) is defined as an erosion phenomenon caused by high-speed droplet attack in a steam flow. Pipe wall thinning by LDI is sometimes observed in a steam piping system of a power plant. As LDI usually occur very locally and is difficult to detect, a prediction of LDI location is required for the safety of the plant system. Therefore, as ultimate objectives, we set the development of the prediction tool of LDI location that can use in power plants easily.
In previous researches, we had developed LDI evaluation system to evaluate the thinning rate and shape by LDI within an acceptable time. However, in the present system, existing models were applied to predict the thinning rate and this sometimes estimates thinning rate over-conservatively because their model did not consider the cushioning effect of liquid film on the material caused by the droplet attack.
Therefore, in this study, we conducted LDI experiment with steam experiment apparatus and tried to develop a new thinning rate prediction model (LDI model). High-speed steam-water two-phase flow which is same as an actual plant condition was used in this experiment. As a result, a cushioning effect of liquid film was reproduced and was incorporated into LDI model as a correlation equation with fluid parameter.

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