超同期旋回キャビテーションの発生に及ぼすインデューサ回転数の影響

抄録

Cavitation is a phase change phenomenon from liquid to gas phase that occurs in low-pressure regions of high-speed fluid machinery such as rocket turbopumps. In particular, the phenomenon that a cavity rotates faster than rotational speed of the pump in the direction of rotation is called super-synchronous rotating cavitation (super-S RC). Cavitation are known to cause vibration, noise and decrease of efficiency. Therefore, understanding characteristics of occurrence of cavitation is significant. It is known that super-S RC is often observed in rocket turbopumps, but that in industrial pumps it is not observed. For this reason, it is estimated that its occurrence is related to rotational frequency of pumps. In this study, experiments of an inducer were conducted at two types of rotating speed at Kakuda Space Center in the Japan Aerospace Exploration Agency. By the rotating speed of the motor and the mean flow rate is held constant and the inlet pressure decline, pressure fluctuation was measured, and the ranges of cavitation number where super-S RC occurred were compared. As a result, super-S RC is observed at higher range of cavitation number when rotating speed is low.