気泡流モデルキャビテーション流れ解析による遠心ポンプ内のキャビテーション強さおよびエロージョン発生頸域の予測

摘要

ポンプの高速小型化を図る際，製品の強度信頼性をrn確保するためには，キャビテーションエロージョンのrn予測が重要な課題となる．現在，ポンプのエロージョrnン予測は主に実験的な手法で行われているが，rn流体解析が活用できれば試験の省力化が可能となり，rn開発期間の短縮等に対する効果は大きい．例えば，キrnャビテーション長さを用いた実験式は代表的なrnエロージョン予測法の一つであるが，従来実験的に求rnめていたキャビテーション長さを流れ解析で予測するrnことが試みられている．%We developed a numerical simulation code and an estimation method for predicting the cavitation erosion in pumps. The cavitation erosion is closely related to the cavitation intensity based on the bubble dynamics. A 'bubble flow model' simulates the detailed bubble behavior in a cavitating flow. The cavitation intensity was estimated by analyzing the bubble pressure and the bubble nuclei distribution in a centrifugal pump. We simulated impulsive bubble pressure that varied in microseconds. The impulsive pressure is considered to be related to actual bubble collapse, which causes the cavitation erosion. The erosion area was experimentally detected using a paint method. The predicted high cavitation intensity area agreed well with the experimental erosion area, since the predicted and experimental areas were both located between the shroud and mid point of the blade near the leading edge. Our code is thus effective for estimating the cavitation intensity and predicting the erosion area around the impeller of a centrifugal pump.