The central objective of this study is to investigate the effectiveness of implementing a plasma discharge to improve combustor dynamics and flame stability. Specifically, a nano-second pulsed plasma discharge (NSPD) was applied to a premixed gaseous fuel/air dump combustor for mitigation of dynamic combustion instabilities with a minimal NOX penalty. This paper addresses the scaling of this technology from ambient pressure and temperature conditions to more realistic gas turbine combustor conditions.
A model combustor operating at representative conditions of O (102) m/s flow velocity, ∼ 580 K combustor inlet temperature, and ∼ 5 atm in-combustor pressure was selected to simulate a typical low-power environment of future aero engine gas turbine combustors. Fully premixed methane or propane was utilized as a fuel. Similar to a previous ambient-pressure study, a significant reduction of pressure fluctuation level was observed, by a factor of 2X to 4X over a wide range of velocity at the baseline temperature and pressure. The plasma power required for the reduction increased linearly with increasing velocity. The change of fuel from methane to propane showed that propane requires significantly (2X) higher plasma power to achieve a similar level of noise reduction. It was also observed that the lean blowout (LBO) limit was significantly extended in the presence of the plasma, however, substantial incomplete combustion occurs in the extended regime. NOX measurements showed that the incremental NOX production due to the presence of the plasma was low (∼ < 1EINOX) in general, however, it increased with decreasing velocity and pressure, and increasing temperature.