Comparison of Stall Point Predictions in a Transonic Axial Compressor Rotor Using Single Passage and Three Passage CFD Geometries

An investigation is presented which compares the predicted stall points and underlying flow fields for single-passage and three-passage CFD geometries of a transonic axial compressor rotor. The two cases are run using the commercial CFD code ANSYS CFX and compared to experimental data. The two predicted stall points are found to differ from each other, and both under-predict the rotor’s performance compared to the experimental data. However, the steady-state flow fields are found to be identical for all operating points short of the stall point. A mechanism is then proposed to reconcile the difference in predicted stall points with the identical steady-state flow fields. By the mechanism proposed, the addition of multiple passages makes flow through the three-blade geometry less stable, which causes the rotor to stall earlier.