Dynamic characteristics of a compressor with blade crack faults

The airflow behavior in the compressor flow field is complex and variable. If cracks occur in the blades, it is easy to induce flow instability and abnormal mechanical vibration. In this paper, a dynamic model of the blade–rotor system considering fluid excitation and external excitation of the motor is established. Through dynamic simulation calculations, the dynamic characteristics of the normal blade–rotor system considering fluid excitation and the cracked blade–rotor system are compared and analyzed. Experimental research on the vibration response of the blade–rotor system is also conducted. The research shows that blade cracks intensify the phenomena of flow separation and shedding vortices, making the flow field characteristic distribution discontinuous and uneven, resulting in increased total pressure loss, reduced efficiency, and decreased work output of the compressor. Cracks cause the fluid excitation on the blades to show a decreasing trend, leading to a reduction in the amplitude of the blade–rotor system vibration response at characteristic frequencies such as the shaft frequency, shaft frequency harmonics, and blade frequency. The research results provide an important theoretical basis for the analysis of compressor blade crack faults.