Abstract: To further improve the performance of the supersonic expander-rotor, a numerical analysis method was presented to study the internal flow characteristics and the loss mechanisms. The simulation results show that the structure of the expansion waves at the inlet of the expansion passage and the oblique shock waves at the outlet of the expansion passage control the 3-D flow structure in the supersonic expander-rotor. The generation, evolution, and breakdown of the tip leakage vortex is the main features for the vortex motion in the supersonic expander-rotor. The flow losses in the supersonic expander-rotor could be divided into four forms:profile loss, endwall loss, leakage loss, and wake loss. The friction loss between boundary layer and strake wall which is distributing on the lower surface of the suction surface is the main form of the profile loss. The losses including flow separation, recirculation, and low energy fluid mixing with mainstream induced by oblique shock waves, and oblique shock waves-oblique shock waves, oblique shock waves-boundary layer interaction is the main source of the endwall loss.

Key words: internal flow characteristics, loss mechanisms, supersonic expander-rotor, tip clearance flow