Optimization Study of the Effect of T-shaped Circumferential Groove Casing Treatment on Transonic Axial Compressor Stability

The aerodynamic stability of highly loaded compressors is a critical factor limiting the development of aircraft engines. Casing treatment has been extensively used due to its simple structure, easy retrofitting, and significant stall margin improvement. This paper investigates the T-shaped circumferential groove casing treatment (TSCGCT), a new geometry for circumferential groove casing treatment (CGCT), under transonic axial compression using numerical simulation methods. The objective of this paper is to investigate the effect of TSCGCT configurations on compressor performance using an optimization approach. A multi-objective optimization platform is established by using compressor stall margin and peak efficiency loss as the optimization objectives. By combining the surrogate model with the multi-objective genetic algorithm, global optimization is performed for five parameters of the T-shaped groove. The distribution characteristics of the Pareto optimal solutions are summarized and the design criterion of the TSCGCT configurations is obtained. In addition, the study reveals the correlation between the Pareto optimal solutions and the change of potential flow mechanisms in the compressor. The study found that the radial transport effect caused by the TSCGCT configuration effectively reduces the blockage caused by the interaction between the shock wave and the blade tip leakage flow (TLF), and improves the stability of the transonic axial flow compressor. With the optimal TSCGCT design, the stability margin of the transonic axial compressor rotor is increased by 9.71%, and the peak efficiency is reduced by only 0.11%. The result indicates that the optimization performed for TSCGCT can obtain the optimal TSCGCT configuration.