Leakage flow control-based leading edge blade tip machined design of an axial flow compressor

To control the blade tip leakage flow and enlarge the stability margin of a compressor, presented was a method for machining the blade tip at the leading edge. A high-energy fluid was introduced from the blade tip clearance at the leading edge and the turning direction of the leakage flow was controlled by the inertia of the incoming flow. A numerical method was adopted to study the influence of nine leading edge blade tip machined structures on the performance of the rotor at various rotating speeds. With an aim to increase the stability margin, an optimized design was performed of the blade tip machined structure. It has been found that with an incoming flow introduced from the leading edge blade tip clearance, the leading edge blade tip machining can lower the return flow extent of the leakage flow, thus decreasing the blocking extent of the passage. Under the premises of the total pressure ratio and isentropic efficiency keeping constant, the stability margin of the rotor was increased by 2% and 3% at the high and low rotating speed respectively. There exists an optimum blade tip machining extent at which a relatively big increment of the stability margin can be obtained by the rotor at various rotating speeds.