Three-dimensional unsteady simulation of a multistage axial compressor with labyrinth seals and its effects on overall performance and flow characteristics

The purpose of this investigation was to explore the effects of leakage flows from labyrinth seals in shrouded stators on the performance and detailed flow characteristics of multistage axial compressors. A three-stage axial compressor with an inlet guide vane operating under transonic conditions was considered. The three-dimensional unsteady Reynolds-averaged Navier-Stokes equation with a shear stress transport turbulence model was employed in the simulation. The transient rotor-stator model was used at the interface between the rotor and stator to consider the flow interaction and propagation from upstream to downstream. The results clearly presented that the leakage flows could reduce the compressor performance due to a disturbance in the main flow. Moreover, it was observed that the leakage, which flowed from the labyrinth seal to the main flow path, can intensify the recirculation characteristics, such as the hub-corner stall. On the other hand, the reversed leakage flows, corresponding to flow from the main flow path to the seal side, reduced the size of the hub-corner stall. In addition, the spanwise total pressure loss characteristics were altered by the size of the recirculation flows due to leakage flows. Thus, the leakage flows could affect the total pressure loss and blockage, which are important parameters in compressor design. (C) 2019 Elsevier Masson SAS. All rights reserved.