A method for evaluating the time-averaged and unsteady characteristics of flow loss in axial compressors

Unsteady flow loss mechanisms in compressors are critical for aerothermodynamic performance. This study proposes a method integrating entropy generation modeling and control volume analysis to evaluate unsteady losses. Using axially, spanwise, and azimuthally divided control volumes with nonlinear harmonic simulations, time-averaged and unsteady entropy generation distributions were analyzed in a transonic axial compressor. Results identified high entropy generation in rotor region, localized at the mid-to-rear chord, trailing edge, and blade tip. Key mechanisms include: 1. Shock wave/boundary layer interaction causing trailing edge boundary layer thickening and entropy generation rise. 2. Shock wave/leakage vortex interaction at the blade tip, involves mixing between the post-shock leakage flow and secondary leakage flow from adjacent passages, generating high entropy generation. 3. Rotor wake and stator leading edge interaction, inducing unsteady low-pressure zones and entropy generation fluctuations in the stator domain. The method effectively quantifies entropy generation and clarifies flow physics, aiding compressor design optimization.