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James D. Paduano. Liao, Shengfang, 1968- Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics. Massachusetts Institute of Technology. Department of Aeronautics and Astronautics 2005-08-23T15:37:31Z 2005-08-23T15:37:31Z 2000 2000 http://hdl.handle.net/1721.1/8823 48384491 Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2000. Includes bibliographical references (p. 123-127). This thesis presents an investigation of the stability of axial compression systems when external disturbances are introduced. Aerodynamic stability is considered from a nonlinear perspective. From this perspective, the goal is to enhance the ability of compressor systems to remain stable in the face of external disturbances. Experiments were conducted on a low-speed three-stage axial compressor. Instead of achieving extension of linearly stable operating range, this research is focused on the followings: (1). The operability of the compressor, the ability of maintaining the stable operations of the compressor near the operating points in the presence of the external disturbances, was considered. The concept of domain of attraction was adopted to characterize the operability or the disturbance rejection of the compressor. An experimental method was developed to generate disturbances and measure the approximate domain of attraction in terms of the zeroth and first mode flow perturbations. (2). Improvement of the approximate domain of attraction was demonstrated by active control. Both the constant gain control which has been used in many range extension tests and the sliding mode control which is model based, doubles the maximum allowable amplitudes of the zeroth and first mode flow perturbations. (3). The downstream bleed was chosen as the actuation, which is easy to implement and more practical. The number of the bleed valves was chosen to be four to compromise the goal of reducing the number of actuators and the requirement of achieving a satisfactory control effectiveness. (4). The domain of attraction was also examined under inlet distortions. The nonlinear simulation showed that the disturbance rejection of the compressor with background distorted flow was improved by active control. by Shengfang Liao. Ph.D. 142 p. 8458119 bytes 8457876 bytes application/pdf application/pdf eng Massachusetts Institute of Technology M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 Aeronautics and Astronautics. Robust control of a surge and rotating stall in an axial compressor Thesis application/pdf false Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="e5b77af7-bcba-4d15-ab4a-700c6f9c49b7"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Robust control of a surge and rotating stall in an axial compressor</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2000</PublicationDate> <Authors> <Author> <DisplayName>Liao, Shengfang, 1968-</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Aeronautics and Astronautics.</Keyword> <Abstract>This thesis presents an investigation of the stability of axial compression systems when external disturbances are introduced. Aerodynamic stability is considered from a nonlinear perspective. From this perspective, the goal is to enhance the ability of compressor systems to remain stable in the face of external disturbances. Experiments were conducted on a low-speed three-stage axial compressor. Instead of achieving extension of linearly stable operating range, this research is focused on the followings: (1). The operability of the compressor, the ability of maintaining the stable operations of the compressor near the operating points in the presence of the external disturbances, was considered. The concept of domain of attraction was adopted to characterize the operability or the disturbance rejection of the compressor. An experimental method was developed to generate disturbances and measure the approximate domain of attraction in terms of the zeroth and first mode flow perturbations. (2). Improvement of the approximate domain of attraction was demonstrated by active control. Both the constant gain control which has been used in many range extension tests and the sliding mode control which is model based, doubles the maximum allowable amplitudes of the zeroth and first mode flow perturbations. (3). The downstream bleed was chosen as the actuation, which is easy to implement and more practical. The number of the bleed valves was chosen to be four to compromise the goal of reducing the number of actuators and the requirement of achieving a satisfactory control effectiveness. (4). The domain of attraction was also examined under inlet distortions. The nonlinear simulation showed that the disturbance rejection of the compressor with background distorted flow was improved by active control.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>