O’Donnell Consulting investigated a failed a turbine exhauster, which is part of a high speed, three-stage centrifugal compressor, used to pump exhaust gases out of a coke oven battery.
All three compressor stages are located on the same shaft and housed in the in a common casing. The third stage compressor suffered severe damage, and caused subsequent damage to the facility. O’Donnell performed finite element, engineering analysis, metallurgical, and material testing on the disk and blades. It was concluded that small flaws that had been detected earlier had not been correctly evaluated, and were growing to critical size during normal operating conditions. As the crack grew, the stresses in the disk increased – to the point of disk rupture.