Feedback Control of Combustion Instabilities: A Case Study in Active Adaptive Control of Complex Physical Systems.

摘要

The technical objectives of the program are: Study active control of combustion instability in a laboratory scale combustor based on fuel flow modulation or an alternative practical means of actuation. Develop a model of the plant taking into account the complex physical mechanisms responsible for screech in a liquid-fueled combustor to help design a robust controller. The model should also account for possible interactions between the controller and the plant. Design a controller to suppress screech based on open-loop frequency response data. Implement the controller and demonstrate active control of speech based on liquid fuel flow modulation. Determine the range of application of the controller in terms of flow rates and equivalence ratios. Assess feasibility of nonadaptive, scheduled and adaptive control strategies to design a robust controller to achieve full-envelope control of combustion instability. Develop a general design process applicable to a practical combustor operating over a wide range of input conditions. Identify promising approaches, select candidate strategies for implementation and test these on the existing combustor. Explore extension of active control to suppress transverse mode high frequency oscillations expected in afterburner screech. Identify performance limits of commercially available hardware and explore alternative means of actuation. (JHD)