Local observer for axial flow aeroengine compressors

Instability phenomena occurred in aeroengines are certainly very undesirable. The unstable flow not only causes a drastic reduction in the performance of the compressor but also can damage to engine´s components during operations. Thus it is necessary and critical to employ various feedback control mechanism to stabilize the system. Current all proposed feedback controllers in literature require the full information of the disturbance at the duct entrance, which is an infinite-dimensional quantity and thus is impossible for a direct on-line measurement in reality. In this paper, we construct a local state observer which can deliver the full information of the disturbance by only sensing on an arbitrarily small area at the duct entrance. The approach relies on the semigroup theory as well as operator spectrum analysis. Numerical simulations are provided to illustrate the effectiveness of the proposed observer by demonstrating different types of flow situations for the aeroengine compressors.