Investigation of the flow mechanisms of affecting compressor performance with axial skewed slots casing treatment

Numerical investigation was performed on an axial-flow compressor rotor with 3D unsteady numerical method to explore the mechanism of slots casing treatment affecting the performance and flow field of axial compressor. The experimental and numerical results showed that the steady operating range of compressor rotor was extended and the compressor efficiency was reduced with casing treatment. The flow mechanisms of affecting compressor performance of the numerical simulation obtained by analyzing the flow-field in compressor with casing treatment, indicating that back flow formed in the slots has the ability to pump and blow the low energy liquids near end wall. Ejected flow formed in the slots inspirited the low velocity air mass of blade tip passage, which can suspend the rotor stall. The work of blade forcing on air in the blade tip was reduced with casing treatment. Back flow and the interaction between back flow and tip mainstream made serious flow loss. Thus, compressor rotor isentropic efficiency was reduced.