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A Study on the Requirements for Fast Active Turbine Tip Clearance Control SystemsThis paper addresses the requirements of a control system for active turbine tip clearance control in a generic commercial turbofan engine through design and analysis. The control objective is to articulate the shroud in the high pressure turbine section in order to maintain a certain clearance set point given several possible engine transient events. The system must also exhibit reasonable robustness to modeling uncertainties and reasonable noise rejection properties. Two actuators were chosen to fulfill such a requirement, both of which possess different levels of technological readiness: electrohydraulic servovalves and piezoelectric stacks. Identification of design constraints, desired actuator parameters, and actuator limitations are addressed in depth; all of which are intimately tied with the hardware and controller design process. Analytical demonstrations of the performance and robustness characteristics of the two axisymmetric LQG clearance control systems are presented. Takeoff simulation results show that both actuators are capable of maintaining the clearance within acceptable bounds and demonstrate robustness to parameter uncertainty. The present model-based control strategy was employed to demonstrate the tradeoff between performance, control effort, and robustness and to implement optimal state estimation in a noisy engine environment with intent to eliminate ad hoc methods for designing reliable control systems.
Document ID
20040110855
Acquisition Source
Glenn Research Center
Document Type
Technical Memorandum (TM)
Authors
DeCastro, Jonathan A. (QSS Group, Inc. Cleveland, OH, United States)
Melcher, Kevin J. (NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
September 7, 2013
Publication Date
July 1, 2004
Subject Category
Aircraft Propulsion And Power
Report/Patent Number
NASA/TM-2004-213121
E-14615
AIAA Paper 2004-4176
Meeting Information
Meeting: 40th Joint Propulsion Conference and Exhibit
Location: Fort Lauderdale, FL
Country: United States
Start Date: July 11, 2004
End Date: July 14, 2004
Sponsors: American Society for Electrical Engineers, American Society of Mechanical Engineers, Society of Automotive Engineers, Inc., American Inst. of Aeronautics and Astronautics
Funding Number(s)
WBS: WBS 22-714-70-08
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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