Abstract

Coal dust explosions can be hazardous; however, they can also generate a significant rise in stagnation pressure if adequately harnessed. Rotating detonation engine combustors seek to take advantage of the stagnation pressure rise phenomenon in a more sustained and controlled manner via confinement to a physical annulus, leading to increased overall thermodynamic efficiency. This investigation presents an analysis of detonations fueled by Carbon Black, a solid particulate consisting of virtually pure carbon molecules and lean Hydrogen-Air mixtures. As was previously realized with the addition of Carbon Black, an increase of operability limits and detonation velocities over that of a pure Hydrogen-Air interaction exist. For all testing conditions, the total equivalence ratio is held at f = 1, while the fuel mixture's carbon mass fraction is increased from 0 – 0.7. Total mass flow injected into the annulus remained constant (?0.415 kg/s). Detonation wave velocities are extracted from high-speed imaging through applying a Discrete Fourier Transform algorithm to determine changes to speed when Carbon Black particles are introduced. As a result, due to the addition of Carbon Black as an auxiliary fuel source, detonations were formed instead of deflagrations in operating conditions where one would expect deflagrations at the same Hydrogen-Air equivalence ratios without Carbon Black addition. The detonation formation provides evidence that the coal particles are reacting within the detonation wave in a large enough capacity to aid in forming and supporting a detonation wave within the annulus. The detonation wave velocities were found to decrease with hydrogen's incremental replacement with coal particles while maintaining a constant global equivalence ratio. Whereby, through a theoretical comparison of the heat of combustion as computed from the experimentally derived detonation wave velocities, a linear relationship of the two was shown to exist. Therefore, the heat of combustion has the potential to describe an operational limit to sustaining a detonation wave.

Notes

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Graduation Date

2021

Semester

Spring

Advisor

Ahmed, Kareem

Degree

Doctor of Philosophy (Ph.D.)

College

College of Engineering and Computer Science

Department

Mechanical and Aerospace Engineering

Degree Program

Aerospace Engineering

Format

application/pdf

Identifier

CFE0008467

Language

English

Release Date

May 2024

Length of Campus-only Access

3 years

Access Status

Doctoral Dissertation (Campus-only Access)

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