Incorporating the Unsteady Lift Effect of Compressor into Throughflow Solutions

The unsteady lift mechanism in compressors has been suggested by its observed correlation with an increase in total pressure rise as rotor-stator interaction strengthens, such as with a reduction in rotor-stator spacing. This phenomenon is closely associated with the interaction between wake from the upstream blade row and the downstream blades. This study aims to incorporate this unsteady mechanism into the reduced-order methodology commonly employed during the design phase, specifically via throughflow calculations based on the circumferentially-averaged Navier–Stokes (CANS) equations. Within the CANS framework, the unsteady lift effect is represented through deterministic source terms in the momentum and energy equations. To enable practical modeling, an empirical formulation for these terms is proposed based on wake characteristics and a reference length that combines axial spacing and stator chord. The model is validated on a low-speed, highly loaded compressor, where it captures key meridional flow features and performance trends under varying axial gaps. While the model demonstrates promising accuracy for this representative case, further studies are required to evaluate its generalizability and to refine its physical basis.