Abstract

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.

Notes

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Graduation Date

2020

Semester

Summer

Advisor

Ahmed, Kareem

Degree

Master of Science in Aerospace Engineering (M.S.A.E.)

College

College of Engineering and Computer Science

Department

Mechanical and Aerospace Engineering

Degree Program

Aerospace Engineering; Thermofluid Aerodynamic Systems

Format

application/pdf

Identifier

CFE0008156

Language

English

Release Date

August 2025

Length of Campus-only Access

5 years

Access Status

Masters Thesis (Campus-only Access)

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