Visualization of Wave Rotor Inner Flow Dynamics

The design of a wave rotor requires an understanding of the pressure wave dynamics in the rotor passages. The present paper describes a two-dimensional numerical simulation and an experimental visualization of the wave rotor compression process. First, a unique experimental apparatus with fixed cells and rotating ports was constructed for visualization and direct measurements; this arrangement is opposite to the conventional setup. Next, experimental and numerical results were compared to verify the simulation modelling, particularly with regard to the propagation velocity of pressure waves in the passages. Lastly, the effects of gradually opening the passage to the ports and leakage through the clearance, which are considered to be dominant factors in wave rotor operation, on the pressure wave dynamics were carefully investigated. The results showed that the gradual passage opening greatly influences the primary shock wave, whereas the leakage mostly influences the secondary (reflected) shock wave. Moreover, it was revealed that the leakage generates an extra pressure wave during the compression process due to the interaction between adjacent passages.