回転曲がりダクトによる遠心羽根車内の二次流れと損失生成機構の解明（第1報，Rossby数の影響）

摘要

The objective of this study is to reveal the effects of the passage vortex on the loss generation within a centrifugal rnimpeller by numerically analyzing the flow within the rotating curved duct which is considered to be a simplified model for rncentrifugal impeller channels. In a centrifugal impeller, the behavior of passage vortex is strongly influenced by the rncentrifugal force caused by the curvature of the impeller passage and the Coriolis force induced by the rotation. Therefore, rnthe Rossby number, which is defined as the ratio of the former force to the latter, is chosen as the major parameter in the rnpresent study. The computed results revealed that the location of the high loss region at the exit of the bend strongly rndepended on the Rossby number. Moreover, the strength of the secondary flow and the associated losses were remarkably rnincreased by the decrease of the Rossby number less than 1.0.%ターボ機械の羽根車流路内で生じる二次流れおよrnびそれによる損失生成の機構を解明することは，そのrn空力性能の向上のために必要不可欠である．実機の羽rn根車内の二次流れは流路渦，馬蹄形渦や漏れ渦等の複rn数の渦により構成されており，その中で最も支配的なrnものは流路渦である．