Case 43: Containing a failed impeller

摘要

Containing failed rotating parts can be a real safety concern. When a production diesel engine turbocharger impeller came apart the fragments were contained in the housing. Management was concerned that if the high-speed impeller failed again it could burst through the housing and cause injuries. The following analysis was performed to determine how close the impeller was to breaking through the housing. If the analysis indicated it could break through, the design group said it would do the recommended expensive burst testing. Flywheels, rotors and impellers usually fail at the bore into three or more pie-shaped fragments. High-speed photography shows that the pieces tend to move in the direction of rotation.