Experimental and Numerical Investigation of Micro Tip Injection in a High⁃Speed Axial Compressor Rotor

A series of experiments and numerical simulations are carried out in a high-speed axial compressor to systematically investigate the influence and underlying flow mechanisms of micro tip injection on enhancing compressor stability. Different geometric structures of micro tip injection have been investigated, including the axial positions of injector port, injected mass flow rate and injector diameter. First, seven designed micro tip injection structures and one solid wall casing are tested in the compressor test rig to elucidate the influence of different micro tip injection parameters on the compressor stability. Then, numerical simulations are conducted to analyze the underlying flow mechanisms of micro tip injection with different design parameters on enhancing the compressor stability. The experimental and numerical investigation reveal that when the injection port is located upstream of the low-speed region, the compressor stability is significantly enhanced. The tip injection with larger injected mass flow can obtain higher stall margin improvement. Smaller injector diameter produces higher injection momentum and velocity, contributing to greater improvement on the compressor stability.