In the development of a turbopump for rocket engines, the cost is expensive and the period is too long. We apply the gas turbine of the turbocharger for cars of a consumer product to a turbine part, and propose the turbopump for small rocket engines which adopted as the pump part the single-stage turbopump which attained small size and simplification. The mixed-flow impeller, which is effective as the main impeller for suction performance, was used for this pump. Performance was optimized by carrying out ultra-high-speed rotation of the impeller. In this study, the pump performance, suction performance, and internal flow of two kinds of pumps with which blade angles differ were investigated by experiments and numerical analysis. The results showed that the head coefficient of impeller B was improved in comparison with that of impeller A at the design flow rate, thus satisfying the design requirement. However, the critical cavitation number of both impellers does not satisfy the design value. Since the channel is blockaded by a sheet cavity and the cloud cavity, the critical cavitation number of impeller B becomes larger than that of impeller A.

View full abstract

Cavitating flow around a Clark Y 11.7% hydrofoil in a water tunnel is studied experimentally in order to understand the cavitation performance of hydrofoil and its relation to cavitation behaviors. Lift and drag forces are directly measured in various cavitating conditions simultaneously with high-speed video observations and pressure fluctuation measurements. It is confirmed that, the lift force slightly increases with some amount of cavitation and then decreases as the cavitation number is decreased. The cavity behavior is rather stable at the cavitation number with the maximum lift force, and the cavitation instabilities are observed during the decrease of the lift force. At the angle of attack of α=2.0 degree, the increase of the lift is not observed, and the lift force decreases with the occurrence of one of cavitation instabilities.

View full abstract