Active Control of Lean Blowout Using an ANN-Based On-Line Direct Controller

Combustor Lean BlowOut (LBO) is a significant challenge in modern military gas turbine combustors. LBO can occur either during rapid engine deceleration or during operation at idle conditions with water/steam ingestion. Current practice is to design adequate safety margins to avoid the onset of blowout. However, significant engine performance improvements can be realized though the development of a system that identifies and prevents blowout. Such a closed-loop, active control system is proposed for development in this SBIR. In Phase I, experiments were conducted and both chemiluminescence and pressure signal characteristics were identified that precede blowout. A prototype gas turbine injector being developed for JSF application under Navy sponsorship was used to provide a realistic and representative test environment. In Phase II, the complete system will be developed and demonstrated. A novel Artificial Neural Network (ANN) on-line direct controller will be developed to identify LBO precursors in real time and control the fuel injector response. An ANN-based direct controller does not require a system model and the controller automatically adjusts to changing dynamic system conditions. For LBO control, an innovative plasma-based flame stabilization system will be incorporated into the fuel injector and used to stabilize the flame beyond the lean blowout limits by introducing a pulsed corona discharge at the injector exit. CFD Research Corporation will team with Georgia Tech and use their facilities in Phase II.