Aluminum droplet combustion studies using spatiotemporal diagnostics
Wu, Zhiyong LU
(2025)
- Abstract
- Aluminum is a promising carbon-free energy carrier. The combustion of aluminum in steam offers a novel method for the simultaneous production of hydrogen and heat through the reaction: 2Al + 3H2O = Al2O3 + 3H2 + heat. A comprehensive understanding of the combustion mechanism is crucial for predicting and optimizing the performance of aluminum-fueled devices.
This thesis develops different lab-scale aluminum combustion devices and multiple optical diagnostic techniques for flame characterization. Aluminum combustion setups, ranging from single droplets to collective dust flames, are established to provide stable and controllable research targets. The combustion phenomena are inherently complex due to factors such as spatial scales... (More) - Aluminum is a promising carbon-free energy carrier. The combustion of aluminum in steam offers a novel method for the simultaneous production of hydrogen and heat through the reaction: 2Al + 3H2O = Al2O3 + 3H2 + heat. A comprehensive understanding of the combustion mechanism is crucial for predicting and optimizing the performance of aluminum-fueled devices.
This thesis develops different lab-scale aluminum combustion devices and multiple optical diagnostic techniques for flame characterization. Aluminum combustion setups, ranging from single droplets to collective dust flames, are established to provide stable and controllable research targets. The combustion phenomena are inherently complex due to factors such as spatial scales ranging from nanometers to micrometers, transient processes occurring on millisecond timescales, multi-phase dynamics, and extremely high temperatures. To address these challenges, various spatiotemporal diagnostic methods are employed to study key combustion parameters.
A specially designed platform produces single burning aluminum droplets of initial sizes from around 100 µm to 500 µm. The droplets are burning in an adjustable oxidizing environment ranging from an H2O/N2 mixture to an H2O/N2/O2 mixture. The single droplets burning in distinct stages offer unique opportunities for fundamental characterization. Furthermore, a lifted aluminum dust flame is established using aluminum fine powers. This dust flame provides a good target to study flame stabilization, particle-particle interactions, and nano-oxide formation.
Spatiotemporal diagnostic techniques are developed to characterize aluminum flames from different perspectives. First, high-speed incandescence-shadowgraph imaging captures the flame morphology evolution and oxide smoke distribution, simultaneously. The technique determines key parameters, including the flame standoff distance, flame sheet thickness, evaporation rates, and Stefan flow velocity. Second, high-speed RGB pyrometry imaging spatially resolves the surface temperatures of different parts over a burning aluminum droplet and measures the temperature evolution along the wire ignition process and the droplet development process. Then, spatially resolved laser absorption spectroscopy is established to quantify the aluminum atom profile around a burning aluminum droplet. Finally, darkfield and brightfield microscopy quantifies the size and volume of nano-oxide particles in the condensation trail of a jetting aluminum droplet within a dust flame.
With that, the thesis herein contributes key datasets and delivers new knowledge to advance the understanding of aluminum combustion.
(Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/56dc5a26-a052-4bb0-99bc-8e4170250004
- author
- Wu, Zhiyong
LU
- supervisor
- opponent
-
- Prof. Halter, Fabien, University of Orléans, France.
- organization
- publishing date
- 2025-02-18
- type
- Thesis
- publication status
- published
- subject
- keywords
- Aluminum-steam combustion, Single droplet, Aluminum dust flame, Optical diagnostics, Spatiotemporal characterization, Fysicumarkivet A:2025:Wu
- pages
- 86 pages
- publisher
- Division of Combustion Physics, Department of Physics, Lund University
- defense location
- Lecture Hall Rydbergsalen, Department of Physics, Professorsgatan 1, Faculty of Engineering LTH, Lund University, Lund.
- defense date
- 2025-03-28 09:15:00
- ISSN
- 1102-8718
- ISBN
- 978-91-8104-402-7
- 978-91-8104-403-4
- project
- Towards CO2 neutral energy conversion using advanced laser diagnostics and modelling
- language
- English
- LU publication?
- yes
- id
- 56dc5a26-a052-4bb0-99bc-8e4170250004
- date added to LUP
- 2025-02-14 13:45:50
- date last changed
- 2025-07-05 07:48:50
@phdthesis{56dc5a26-a052-4bb0-99bc-8e4170250004,
abstract = {{Aluminum is a promising carbon-free energy carrier. The combustion of aluminum in steam offers a novel method for the simultaneous production of hydrogen and heat through the reaction: 2Al + 3H2O = Al2O3 + 3H2 + heat. A comprehensive understanding of the combustion mechanism is crucial for predicting and optimizing the performance of aluminum-fueled devices.<br/>This thesis develops different lab-scale aluminum combustion devices and multiple optical diagnostic techniques for flame characterization. Aluminum combustion setups, ranging from single droplets to collective dust flames, are established to provide stable and controllable research targets. The combustion phenomena are inherently complex due to factors such as spatial scales ranging from nanometers to micrometers, transient processes occurring on millisecond timescales, multi-phase dynamics, and extremely high temperatures. To address these challenges, various spatiotemporal diagnostic methods are employed to study key combustion parameters.<br/>A specially designed platform produces single burning aluminum droplets of initial sizes from around 100 µm to 500 µm. The droplets are burning in an adjustable oxidizing environment ranging from an H2O/N2 mixture to an H2O/N2/O2 mixture. The single droplets burning in distinct stages offer unique opportunities for fundamental characterization. Furthermore, a lifted aluminum dust flame is established using aluminum fine powers. This dust flame provides a good target to study flame stabilization, particle-particle interactions, and nano-oxide formation.<br/>Spatiotemporal diagnostic techniques are developed to characterize aluminum flames from different perspectives. First, high-speed incandescence-shadowgraph imaging captures the flame morphology evolution and oxide smoke distribution, simultaneously. The technique determines key parameters, including the flame standoff distance, flame sheet thickness, evaporation rates, and Stefan flow velocity. Second, high-speed RGB pyrometry imaging spatially resolves the surface temperatures of different parts over a burning aluminum droplet and measures the temperature evolution along the wire ignition process and the droplet development process. Then, spatially resolved laser absorption spectroscopy is established to quantify the aluminum atom profile around a burning aluminum droplet. Finally, darkfield and brightfield microscopy quantifies the size and volume of nano-oxide particles in the condensation trail of a jetting aluminum droplet within a dust flame.<br/>With that, the thesis herein contributes key datasets and delivers new knowledge to advance the understanding of aluminum combustion.<br/>}},
author = {{Wu, Zhiyong}},
isbn = {{978-91-8104-402-7}},
issn = {{1102-8718}},
keywords = {{Aluminum-steam combustion; Single droplet; Aluminum dust flame; Optical diagnostics; Spatiotemporal characterization; Fysicumarkivet A:2025:Wu}},
language = {{eng}},
month = {{02}},
publisher = {{Division of Combustion Physics, Department of Physics, Lund University}},
school = {{Lund University}},
title = {{Aluminum droplet combustion studies using spatiotemporal diagnostics}},
url = {{https://lup.lub.lu.se/search/files/208393307/Thesis_Zhiyong_Wu_LUCRIS.pdf}},
year = {{2025}},
}