Volume 25, Issue 5 (September 1997)
Ultrasonic Stress Evaluation in a Compressor Rotor
The run-out report for a compressor rotor showed an almost continuous bow between the two bearings. The maximum run-out of 0.03 mm (0.0012 in.) occurred at the inlet to the fourth stage impeller. The steel compressor rotor was just over 3 m in length. It had been removed from service for maintenance. Each of the seven compressor stages was mounted on the rotor at the time of the stress measurement. An evaluation of the residual stress at the inlet locations in the shaft using critically refracted longitudinal, LCR, ultrasonic waves showed compressive stress on the bowed side of the rotor, supporting the conclusion that residual stress is the cause of the bow.