Numerical investigation of a single circumferential groove casing treatment on three different compressor rotors

In axial compressors, casing treatments represent a passive method to increase the working range without the need to modify the blade geometry. The majority of the open literature on the topic considers one or several casing treatment variants on the same compressor. The question how one casing treatment and its basic mechanisms can be transferred to a different compressor is only covered in a small number of publications. This paper tries to fill this gap by applying a single circumferential groove type casing treatment to three different transonic compressor rotors. It is demonstrated numerically that the casing treatment is able to improve the aerodynamic performance of all three rotors. Detailed investigation of the flow field near the rotor tip shows that the single circumferential groove works by influencing the interaction between the tip clearance vortex and the shock. Hence, this type of casing treatment can be generalized to transonic rotors with a stall mechanism that is based on tip clearance vortexshock interaction.