Airflow pressure pulsation of contra-rotating fan and its influence on the motor

As the two-stage impellers of contra-rotating fan are directly connected to the motor shaft, the load torque pulsation may affect the electromagnetic torque and rotating speed of the driving motor. A contra-rotating fan as FBD5.0/2 × 7.5 for coal mining is studied. A 3D physical model of contra-rotating fan is firstly built. A total of 12 monitoring points on 4 interference planes at the inlets and outlets of the two-stage impellers are set. The air pressure changing with time for every monitoring point is obtained. According to the air pressure pulsation of the impeller torque, the electromagnetic torque and rotating speed of the driving motor are gotten. The results are important for determining the load capability of the driving motor with a fan.