0433 遠心ポンプに発生するキャビテーションの熱力学的効果(OS4-7 流体機械の研究開発とそれに関連した複雑流動現象,OS4 流体機械の研究開発とそれに関連した複雑流動現象)

Abstract

The thermodynamic effect which affects the cavitation performance of a cavitating centrifugal pump was investigated experimentally using liquid nitrogen. To measure the pump cavitation performance, a test setup which could carry out experiments using both liquid nitrogen and cold water was constructed. The test pump was a centrifugal type magnetic pump, and two impellers, which differed in cavitation performance, were used in experiments. The experimental results indicated that cavitation performance using liquid nitrogen was better than that using cold water due to the thermodynamic effect of cavitation. The estimated temperature depression due to the thermodynamic effect decreased with a decreasing flow coefficient. And it was shown that the estimated temperature depression on the low cavitation performance impeller was larger than that on the high cavitation performance impeller at the same flow coefficient. Moreover, nondimensional thermodynamic parameter Σ* of present study shows a large value comparing with other previous studies. It was indicated that the thermodynamic effect of the cavitation using the centrifugal pump on present study is stronger than that of other previous studies.