Digtial Simulation of an Active Control System of Compressor Stall Based on Injection

Li Jun, Chu Wuli, Zhu Junqiang, Liu Zhiwei
(Northwestern Polytechnical University)
Xu Gang (Qing Hua University, Beijing)

Abstract: In this paper, a control system is constructed in theory to be used for active of rotating in an axial-flow compressor. The inlet injection is taken as the actuator of this control system. The control system is composed of five parts, such as the signals acquisition, harmonic analysis, the stall precursor pickup, the reconstruction of control signals and inlet injection actuator. The mathematic models of every parts of control system and compression system are derived. The model of compression system is the modified Moore-Greitzer model including inlet injections. Eight inlet flow coefficients are taken as the signals of rotating stall. The time lag of acquisition system is negligible. The harmonic analysis o f stall signals and stall percursor pickup are based on SFC analysis method and the linearity examination of the phase of harmonics varying with time respective ly. The reconstruction of control signals obeys the proportion feed law. The injection actuator is modeled as first-order lag. The digital methods, Mac Cormack's scheme and four-order Runge-Kutta method, are used to solve the equations of control system and compression system. Three simulation results, the development of rotating stall without any control and the responses of compression system with continuous control and discontinuous control respectively, are showed. The simulation results demonstrate that the rotating waves are able to be suppressed efficiently by means of the active control system proposed in this paper, and the compressor operation points are on the axial-symmetric characteristic curves .
Keywords: compressor stall, active control system, simulation.