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International Journal of Rotating Machinery
Volume 2017, Article ID 7529716, 14 pages
https://doi.org/10.1155/2017/7529716
Research Article

Application of System Identification for Modeling the Dynamic Behavior of Axial Flow Compressor Dynamics

1Department of Mechanical Engineering, Idaho State University, Mail Stop 8060, Pocatello, ID 83209, USA
2Institute of Engineering Thermophysics, CAS, 11 Beisihuanxi Road, Beijing 100190, China

Correspondence should be addressed to Marco P. Schoen; ude.usi@cramohcs

Received 1 February 2017; Accepted 11 April 2017; Published 7 May 2017

Academic Editor: Pietro Zunino

Copyright © 2017 Marco P. Schoen and Ji-Chao Lee. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Identification of a one-stage axial compressor system is addressed. In particular, we investigate the underlying dynamics of tip air injection and throttle activation to the overall compressor dynamics and the dynamics around the tip of the compressor blades. A proposed subspace system identification algorithm is used to extract three mathematical models: relating the tip air injection to the overall dynamics of the compressor and to the flow dynamics at the tip of the compressor blade and relating the movement of the throttle to the overall compressor dynamics. As the system identification relays on experimental data, concerns about the noise level and unmodeled system dynamics are addressed by experimenting with two model structures. The identification algorithm entails a heuristic optimization that allows for inspection of the results with respect to unmodeled system dynamics. The results of the proposed system identification algorithm show that the assumed model structure for the system identification algorithm takes on an important role in defining the coupling characteristics. A new measure for the flow state in the blade passage is proposed and used in characterizing the dynamics at the tip of the compressor blade, which allows for the inspection of the limits for the utilized actuation.