Dynamics and stability of lean-premixed swirl-stabilized combustion

Bifurcation control deals with modification of bifurcation characteristics of a parameterized nonlinear system by a designed control input. Typical bifurcation control objectives include delaying t...

/pdf/bifurcation-control-theories-methods-and-applications-2x17nw7jh6.pdf

Bifurcation control: theories, methods, and applications

: This book has several purposes, including a broad historical summary of combustion instabilities in propulsion systems; a concise compilation of the main mechanisms for instabilities in liquid and solid fueled rockets, ramjets, thrust augmentors and gas turbines; development of a theoretical framework for investigating unsteady motions in combustion systems; and accessible surveys of the basic material required to understand the subject. Emphasis is placed throughout the book on observed behavior. For well-understood reasons, the best, and in many respects most useful quantitative data, have been obtained for solid propellant rockets. Hence that type of device occupies a special position in the subject. The book comprises nine chapters and eight annexes. Material in the annexes is not essential for reading and broadly understanding the main part of the book, but is likely interesting for those choosing to do research on the subject. The nine chapters divide into three parts.

Unsteady Motions in Combustion Chambers for Propulsion Systems

A review of active control approaches in stabilizing combustion systems in aerospace industry

A practical active control system for t nitigation of combustion instability has been designed and demonstrated in a lean, premixed, single-nozzle combustor at realistic engine operating conditions A full-scale engine fuel nozzle was modified to incorporate a simple fuel flow actuator Results indicate that the system was capable of reducing pressure fluctuations by 82 percent (15 dB or 56×) while maintaining or reducing NO x and CO emissions levels

Active control of combustion instability in a liquid-fueled low-NOx combustor

A number of recent articles have demonstrated the use of active control to mitigate the effects of combustion instability in afterburner and dump combustor applications. In these applications, cyclic injection of small quantities of control fuel has been proposed to counteract the periodic heat release that contributes to undesired pressure oscillations. This same technique may also be useful to mitigate oscillations in gas turbine combustors, especially in test rig combustors characterized by acoustic modes that do not exist in the final engine configuration. To address this issue, the present paper reports on active control of a subscale, atmospheric pressure nozzle/combustor arrangement. The fuel is natural gas. Cyclic injection of 14% control fuel in a premix fuel nozzle is shown to reduce oscillating pressure amplitude by a factor of 0.30 (i.e., {approximately}10 dB) at 300 Hz. Measurement of the oscillating heat release is also reported.

/pdf/combustion-oscillation-control-by-cyclic-fuel-injection-2o63qrho6s.pdf

Combustion Oscillation Control by Cyclic Fuel Injection

/pdf/combustion-oscillation-control-by-cyclic-fuel-injection-2tb8tspqh2.pdf

E. Robey

Papers

Combustion Oscillation Control by Cyclic Fuel Injection

Combustion Oscillation Control by Cyclic Fuel Injection