Keywords

Combustion, Power Generation, Hydrogen, Flame Stabilization

Abstract

The injection of varying fuel-air mixtures into a vitiated, high-speed crossflow is investigated at five atmosphere chamber pressure in this work. The experimental facility has two combustion stages: a headend stage to create the vitiated crossflow and an axial stage injected into an optically accessible test section. The crossflow entered the test section at a velocity of 76 m/s and a temperature of 1750 K. The axial jet mixtures were first investigated at lean equivalence ratio conditions with hydrogen fuel mole fractions up to 100% to study hydrogen enrichment at lower reactivity. Separately, axial hydrogen fuel content was increased at a constant flame temperature of about 1770K to better understand the jet behavior at temperature conditions relevant to power generation industry combustors. The jet velocity for these cases is maintained at 120 m/s to investigate an increased momentum flux ratio. High-speed chemiluminescence was utilized to examine the flame behavior of the reacting jets. Additionally, emissions measurements were taken to quantify the increase in NOx emissions that is expected to occur with larger hydrogen fuel contents. Particle image velocimetry (PIV) imaging was taken for select points to obtain information on the flow field dynamics. For the methane air jets, increasing premixing led to reduced flame stability within the test section viewing window at the equivalence ratios tested Increasing jet hydrogen fraction leads to greater stabilization of the leeward jet flame near the axial injector location the tested equivalence ratios, and the stabilization of a windward flame not present in the methane jets at these velocities. Higher levels of NOx emissions were found to occur with increased equivalence ratio and reduced premixing, which are tied to reduced flame liftoff height, and when a scaling factor is applied higher jet hydrogen levels also led to increased emissions.

Completion Date

2024

Semester

Spring

Committee Chair

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

Language

English

Rights

In copyright

Release Date

May 2029

Length of Campus-only Access

5 years

Access Status

Doctoral Dissertation (Campus-only Access)

Campus Location

Orlando (Main) Campus

Accessibility Status

Meets minimum standards for ETDs/HUTs

Restricted to the UCF community until May 2029; it will then be open access.

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