Assessment of curvature correction and reattachment modification into the shear stress transport model within the subsonic axial compressor simulations

Abstract

Complicated flows featuring with highly three-dimensionality and intense rotation/curvature in turbomachines have made the steady Reynolds-averaged Navier–Stokes (RANS) simulation very difficult. In this paper, based on the widely used ω-based shear stress transport (SST) model, two modifications (one is denoted as shear stress transport model with curvature correction (SST-CC), the other is denoted as shear stress transport model with reattachment modification (SST-RM)) are assessed in predicting the tip leakage flow in the rotor passage and the three-dimensional separating flow in the stator passage of a low-speed axial compressor. Based on the comprehensive experimental data, including the compressor characteristics lines, inter-blade-row velocity profiles, and also detailed three-dimensional flows inside both rotor and stator passages, the abilities for capturing both compressor performance characteristics and specific flow details for simulations with different turbulence models were analyzed. The results indicate that the SST-CC model could simulate an approximate operating line with the one simulated by the SST model, which is very close to the experimental results, while the SST-RM model over-predicted the compressor pressure rise characteristics at all mass-flow-rate conditions. For the tip leakage flow inside the rotor passage and the three-dimensional separating flow inside the stator passage, the SST-RM model predicts a more accurate result, while for the outlet flow profile of the rotor and the stator passage the SST-CC model could simulate a more anastomotic result. In conclusion, the SST-RM model has advantage in predicting the flow fields within the blade rows, while the SST-CC model is adept in predicting the inter-row flow profiles. However, neither of them could simulate great comprehensive results in the investigated axial compressor.