Lean Blowout Sensing and Plasma Actuation of Non-Premixed Flames

The aim of this paper is the use of optical sensors to recognize lean blowout in a non-premixed methane/air burner, Bunsen-type, and the use of plasma actuators for flame control and stabilization. The burner is optically accessible to permit the imaging acquisitions of the flame region. The plasma actuation regards alternatively the air flow and the fuel flow. The electric field is generated using a fixed configuration of plasma actuator and the dielectric barrier discharge (DBD) but using two different power supplies: a nanosecond repetitively pulsed high voltage (HV) and a sinusoidal DBD HV. The comparison between the two types of actuation is the core of this paper, together with the analysis of the results obtained when actuation acted on the air or on the fuel. For the analysis, the lean blowout (LBO) limits recorded in the presence and absence of plasma actuation to investigate the plasma actuation success. The flame behavior is acquired using a compact digital camera, an intensified charge-coupled device (CCD) in order to capture the differences between the baseline conditions and the actuated cases. It is shown that the plasma significantly allows stabilizing the flame under lean conditions where it would not exist without plasma.