Theoretical comparison of non-axisymmetric air injection control of rotating stall on axial flow compressors

Abstract

Nonaxisymmetric air injection control of stall is studied. Three existing control algorithms found in literature are modeled and analyzed. A three-state model is obtained for each algorithm. For two cases, conditions for linear stability and bifurcation criticality on control of rotating stall are derived and expressed in terms of implementation-oriented variables such as number of injectors. For the third case, bifurcation criticality conditions are not obtained due to complexity, though linear stability property is derived. A theoretical comparison between the three algorithms is made via the use of low-order models to investigate pros and cons of the algorithms in the context of operability.