EXPERIMENTAL STUDY OF AERATED TWO-PHASE FLOW PATTERNS IN TANDEM CASCADE

摘要

Difficulty of aerated two-phase flow study lies in the complex flow mechanism and strict experiment requirments. Here controllable aerated two-phase flow passing through the cascade assembled by three Hydrofoil 915 foils is studied. Flow patterns are focused and mutual interactions between solid boundary and flow are described. An experimental rig is built and three hydrofoils are placed with different configurations in a transparent part of the circulation system. High speed photography technique is adopted to record the transient variations of the bubbly flow patterns. A computer aided data collection system is installed to record the data signals and store them into a database. The experimental results show: (1)general flow patterns exist in the flow passing through the tandem cascade; (2)near the trailing edges, intense interaction can be found among wake vortices, trailing jet and pressure gradient; (3)different types of cavitation evolution are predicted to occur at different parts of the cascade.