Recent development of casing treatments for aero-engine compressors

Casing treatment is a mature stabilization technique which has been widely applied on aero-engines for modern aircrafts and turbo-chargers for automobiles. After the investigations of half century since the 1960s, this technique has been well developed for various configurations with different effectiveness. From the perspective of stabilization mechanism, this paper roughly categorizes the configurations of casing treatment into two types: traditional ones which work by affecting the flow structure of blade tip region; a novel one named as Stall Precursor-Suppressed (SPS) casing treatment. The effectiveness of both types will be demonstrated for their applications on axial compressors and centrifugal compressors with uniform or distorted inlet. And the stabilization mechanism of casing treatments for regular types and SPS one will also be explained respectively. In addition, this review will summarize the methodologies of casing treatments with the numerical simulations for regular grooved configurations and the eigenvalue approach for SPS casing treatment. Looking forward to the future of compressor stabilization, casing treatment technique will still exist as a general and inexpensive option, and the exploration for its effectiveness and mechanism will be deeper with the development of computational fluid dynamics and advanced measurement techniques.