RESEARCH PROGRESS OF ADAPTIVE CONTROL METHODS FOR COMPRESSOR FLOW STABILITY

Adaptive control of compressor flow stability is a key technology of intelligent aeroengine in the future. Basic research needs to answer three concerns. How to describe the system stability? How to change the system stability? How to monitor the system stability? Therefore, our team has carried out systematic and in-depth research work in three aspects: general theory of compressor flow stability, stability margin enhancement method based on wall impedance boundary and real-time stall warning technology. (1) The developed general theory of flow instability in turbomachinery not only can consider the flow non-uniformity and blade geometry, but also has high calculation efficiency and great prediction accuracy, which provides a reliable evaluation tool for the integrated design of compressor aerodynamics and stability. (2) The developed SPS (stall precursor-suppressed) casing treatment and foam metal casing treatment based on wall impedance boundary control strategy have made substantial progress in enhancing stability margin and reducing noise while maintaining the aerodynamic performance of the compressor system. Equivalent distributed source method is employed to establish the stall inception prediction model considering the effect of casing, which is able to make sensitivity analysis on crucial structural parameters of SPS casing treatment and foam metal casing treatment so as to provide the clear theoretical design criterion. The experimental results show that SPS casing treatment achieves the purpose of stability enhancement by restraining the nonlinear evolution of stall precursor wave, while maintaining the pressure ratio and efficiency characteristics of the compressor; Foam metal casing treatment has favorable engineering application prospects for its double effects of improving stability and reducing noise. (3) The developed real-time stall warning approach based on aeroacoustic principle increases the stall warning time to more than seconds, and can monitor the system stability online. Combining the above theoretical prediction method, stability enhancement technology and real-time stall warning approach, the closed-loop feedback adaptive control method is developed, which provides an adaptive stability control technology for the future intelligent aeroengine.