ORCID

https://orcid.org/0000-0002-4605-0543

Keywords

Detonation, Proplusion

Abstract

Hypersonic propulsion via scramjets and detonation engines is enabled through the acute understanding of deflagrations, detonations, and multiphase interactions. Deflagrations are explored to understand the compressible flame regime for scramjet unstart and detonation transition in reacting systems. Compressible flames are experimentally classified with a comprehensive diagnostic suite combining particle image velocimetry (PIV), chemiluminescence, schlieren, and pressure measurements in a turbulent shock tube. Several gaseous fuels are explored to identify the universal mechanism responsible for flame compressibility and acceleration. The ability to compress deflagrations and accelerate the system to a detonation directly relies in the successful conversion of energy available to the flow. This is further explored for gaseous detonations where the role of chemical timescales is studied through both the activation energy and the heat release rate of a mixture. In detonation, it is experimentally found through both shadowgraph and chemiluminescence measurements in a narrow channel detonation facility that mixtures with high heat release rates and low activation energy produce the most regular and efficient systems. However, when transitioning technology to hypersonic engines, multiphase flows must be considered. Favorably, most liquid fuels provide extremely elevated levels of heat release rates due to their high energy density. However, liquid fuel must be converted to a usable source of energy under short residence times for the detonation wave. The consumption and gasification of liquid fuel is experimentally captured in a liquid detonation, with monodisperse droplets initially at 5 μm, using Mie scattering at a rate of 200 MHz through a novel technique. Ultimately, the research presented explores how deflagrations accelerate to a detonation, maintain self-sustained propagation, and convert liquid fuel into consumable energy under short residence times.

Completion Date

2025

Semester

Fall

Committee Chair

Kareem Ahmed

Degree

Doctor of Philosophy (Ph.D.)

College

College of Engineering and Computer Science

Department

Mechanical and Aerospace Engineering

Format

PDF

Identifier

DP0029789

Document Type

Thesis

Campus Location

Orlando (Main) Campus

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