Abstract: To investigate the stall mechanism of a transonic compressor with inlet total temperature distortion, full annular un-steady numerical simulations with a 500k, 180-degree circumferential total temperature distortion are conducted on the German Darmstadt transonic compressor. The results indicate that the mass flow rate and the total pressure ratio decrease dramatically under the inlet total temperature distortion. The total pressure radial distribution varies at different circumferential positions on the compressor rotor exit. Along the rotor rotating direction, the total pressure gradually decreases in the high temperature region, and gradually increases in the low temperature region. The closer to the stall point, the greater non-uniform of the total pressure radial distribution. As the mass flow is further reduced, the type of the inception induced stall is spike, and it appears first when the rotor blades turn into the high total temperature region. The circumferential propagation speed of the stall inception is about 88.9% of rotor speed, and the circumferential propagation speed of the stall cells at the beginning of the stall is about 66% of rotor speed. The entire stall process is accompanied by a significant fluctuation of the mass flow, caused by the movement and merging of the stall cells along the circumferential direction.

Key words: total temperature distortion, transonic compressor, unsteady flow, rotating stall, spike type