21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-5.8.2

ACTIVE COMBUSTION CONTROL FOR PROPULSION SYSTEMS

Schadow K. C., Parr T. P., Yu K. H.
Naval Air Warfare Center, CA, USA

Keywords: active, combustion control, propulsion systems

Active combustion control (ACC) is increasingly becoming a candidate to meet the challenges of future combustor designs, which cannot be met within traditional (passive) design approaches. The paper will review the current status based on three recent activities: (1) a workshop, (2) a collaborative program to demonstrate closed loop control of a generic dump combustor using diode laser sensors and advanced controller, and (3) two research programs to apply the detailed understanding of fluid dynamic/combustion/acoustics interactions to active control of liquid and gaseous fuel dump combustors. Pulsed fuel injection from an active control approach will be emphasized. At the present time, one successful full-scale ACC propulsion application has been openly reported for a lean premix combustor. For other applications, forecasts generally rest on laboratory demonstrations without full understanding of the scaling laws. Needs for research and development will be identified to improve physical understanding and to develop sensors, actuators, and control laws. The majority of the present work uses ACC to suppress oscillations. Other applications are equally important. One example is the use of actively controlled vortex combustion to enhance combustion and reduce pollution in compact designs. Closed-loop experiments and scale-up experiments of this approach are being discussed. This concept is also explored for instability control in liquid fuel ramjets by controlling the temporal and spatial droplet distribution.

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