The enhanced growth of ignition kernels through modulation of nanosecond pulsed high-frequency discharges is investigated quantitatively in a reactive flow. High-frequency discharge and new notions of rotational temperature coupling per subsequent pulse ( < 30 kHz) existing within the breakdown regime have led to the discovery of the "fully-recoupled" regime. The evolution of flame kernels is observed in a methane-air mixture at an equivalence ratio of 0.6 flowing at 12.5 m/s, with an interelectrode gap of 1.7 mm. Energy deposition into the flow per pulse was previously found to be 2.9 ± 0.23 mJ/pulse, where the number of pulses per effective modulation type was 10 ( ≈ 30mJ). By holding A.P. (average power) constant through each pulse train, the CPRF (Constant Pulse Repetition Frequency) partially-coupled and decoupled regimes were directly compared against the MPRF (Modulated Pulse Repetition Frequency) fully-recoupled regime through kernel growth measurements via high-speed schlieren. It was found that by utilizing the inter-pulse coupling of rotational temperatures through modulating the PRF (Pulse Repetition Frequency), the ignition probability and kernel area increased as to create the fully-recoupled regime as a new form of ignition optimization.
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Master of Science in Aerospace Engineering (M.S.A.E.)
College of Engineering and Computer Science
Mechanical and Aerospace Engineering
Aerospace Engineering; Thermofluid Aerodynamic Systems
Length of Campus-only Access
Masters Thesis (Campus-only Access)
Dunn, Ian, "Flame Kernel Ignition and Evolution Induced by Modulated Nanosecond-Pulsed High-Frequency Discharge" (2020). Electronic Theses and Dissertations, 2020-. 207.