Investigation into the effects of abradable evolution and ovalisation during blade-casing interactions

Abstract

For maximum aero engine efficiency and performance, the blade tip clearance needs to be minimised. However, this increases the likelihood of blade-casing interactions arising from hard landings, thermal expansion effects of split casings, and turbulence. This work presents a novel experimental setup for investigating the effects of both single and double rubs per revolution, with the latter being representative of engine ovalisation conditions. The results show the difference in response for single and double rub tests, between interactions with virgin and worn abradables as well as in the abradable wear mechanisms. Finally, a blade casing interaction model was introduced to validate the different blade frequency responses seen during aligned single, misaligned single, and aligned double rubs.